The correct answer is HELLO because when you call print(obj), Python automatically invokes the object’s __str__ method, which is designed for readable output and must return a string. In this code, the __str__ method explicitly returns the string 'HELLO', so that is exactly what gets printed, regardless of any other class attributes like x. On the Certified Associate Python Programmer PCAP exam, this question tests your understanding of how __str__ overrides the default string representation of an object, a common topic in the “Object-Oriented Programming” domain. A frequent trap is assuming the class attribute x would be used in the output, but __str__ only returns what you code inside it—here, it ignores x entirely. To remember this, think: __str__ is for “string for humans,” and it always returns the string you explicitly define, not the class data unless you tell it to.
PCAP Object-Oriented Programming Practice Question
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
HELLO
Option B is correct because the code defines a class `X` with a class attribute `x = 'Default x'` and a `__str__` method that returns `'HELLO'`. When `print(obj)` is called, Python invokes the `__str__` method of the object, which returns `'HELLO'`, so the output is `HELLO`. The class attribute `x` is never accessed in the `__str__` method, so it is ignored.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Default x
Why it's wrong here
__getattr__ is not invoked because 'x' exists in __dict__.
✓
HELLO
Why this is correct
Correct: __setattr__ converts to uppercase.
Related concept
Read the scenario before looking for a memorised answer.
✗
hello
Why it's wrong here
The value is uppercased by __setattr__.
✗
AttributeError
Why it's wrong here
No error; attribute is set.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Python Institute often tests the distinction between class attributes and the `__str__` method, trapping candidates who assume that a class attribute named `x` will be printed automatically, rather than recognizing that `__str__` defines the output explicitly.
Detailed technical explanation
How to think about this question
The `__str__` method is a special dunder method in Python that defines the informal string representation of an object, called by `print()` and `str()`. If `__str__` is not defined, Python falls back to `__repr__`. In this code, the class attribute `x` is accessible via `self.x` or `X.x`, but it is not used in the `__str__` method, so it does not affect the output. A real-world scenario is customizing object display in logging or user interfaces.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Object-Oriented Programming — This question tests Object-Oriented Programming — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: HELLO — Option B is correct because the code defines a class `X` with a class attribute `x = 'Default x'` and a `__str__` method that returns `'HELLO'`. When `print(obj)` is called, Python invokes the `__str__` method of the object, which returns `'HELLO'`, so the output is `HELLO`. The class attribute `x` is never accessed in the `__str__` method, so it is ignored.
What should I do if I get this PCAP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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