This PCAP practice question tests your understanding of object-oriented programming. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer defines a class hierarchy with multiple inheritance: class A, class B(A), class C(A), class D(B,C). The method 'm' is defined only in A. What is the method resolution order for D according to the C3 linearization algorithm?
D -> B -> A -> object
Why wrong: This omits C entirely.
D -> B -> C -> A -> object
Why wrong: This includes object, but the MRO includes all base classes up to object.
D -> B -> C -> A
C3 linearization for D(B,C) yields D, B, C, A.
D -> B -> A -> C
Why wrong: This is a naive depth-first left-to-right order, but C3 linearization is used in Python.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
D -> B -> C -> A
C is correct because the C3 linearization algorithm merges the linearizations of parent classes while preserving local precedence order and monotonicity. For class D(B, C), the linearization is D + merge(L(B), L(C), [B, C]). L(B) = B, A, object; L(C) = C, A, object. Merging yields D, B, C, A, object (object is often omitted in option lists). This respects that B precedes C in D's bases and that A appears after both B and C.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
D -> B -> A -> object
Why it's wrong here
This omits C entirely.
D -> B -> C -> A -> object
Why it's wrong here
This includes object, but the MRO includes all base classes up to object.
D -> B -> C -> A
Why this is correct
C3 linearization for D(B,C) yields D, B, C, A.
Related concept
Read the scenario before looking for a memorised answer.
D -> B -> A -> C
Why it's wrong here
This is a naive depth-first left-to-right order, but C3 linearization is used in Python.
Common exam traps
Python Institute often tests the misconception that the MRO follows a simple depth-first left-to-right order, causing candidates to pick option A (D, B, A, C) or D (D, B, A, C) instead of the correct C3 merge result that respects the order of parent classes and their linearizations.
Detailed technical explanation
The C3 linearization algorithm, used by Python for method resolution in multiple inheritance, ensures that a class's MRO is consistent with the local precedence order of its bases and the MROs of all parent classes. Under the hood, the merge operation repeatedly picks the first head that does not appear in the tail of any other list, guaranteeing monotonicity — a property that prevents subtle bugs when subclassing. In real-world frameworks like Django or GUI toolkits, incorrect MRO assumptions can lead to unexpected method calls or attribute lookups, especially with diamond inheritance patterns.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Object-Oriented Programming — study guide chapter
Learn the concepts, then practise the questions
Object-Oriented Programming practice questions
Targeted practice on this topic area only
All PCAP questions
511 questions across all exam domains
Certified Associate Python Programmer PCAP study guide
Full concept coverage aligned to exam objectives
PCAP practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise PCAP questions linked to Modules and Packages.
Practise PCAP questions linked to Strings.
Practise PCAP questions linked to Object-Oriented Programming.
Practise PCAP questions linked to Exceptions and File I/O.
Practise PCAP questions linked to PCAP fundamentals.
Practise PCAP questions linked to PCAP scenario.
Practise PCAP questions linked to PCAP troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Object-Oriented Programming — This question tests Object-Oriented Programming — Read the scenario before looking for a memorised answer..
The correct answer is: D -> B -> C -> A — C is correct because the C3 linearization algorithm merges the linearizations of parent classes while preserving local precedence order and monotonicity. For class D(B, C), the linearization is D + merge(L(B), L(C), [B, C]). L(B) = B, A, object; L(C) = C, A, object. Merging yields D, B, C, A, object (object is often omitted in option lists). This respects that B precedes C in D's bases and that A appears after both B and C.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 30, 2026
This PCAP practice question is part of Courseiva's free Python Institute certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCAP exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.