Quick Answer
The correct answer is that a NullReferenceException is classified as a runtime error. This type of error occurs during program execution, specifically when code attempts to access or use an object reference that currently points to nothing, or null, in memory. Unlike syntax or compile-time errors, which are caught by the compiler before the program runs, a runtime error like NullReferenceException only appears while the application is actively running, often causing it to crash. On the CompTIA ITF+ FC0-U61 exam, this question tests your ability to distinguish error categories: syntax errors are caught at compile time, compile errors prevent the program from building, and logic errors produce incorrect output without throwing exceptions. A common trap is confusing runtime errors with logic errors, but remember that runtime errors generate explicit exception messages, while logic errors silently produce wrong results. A helpful memory tip: if the error happens “live” during execution, it’s a runtime error—think of it as the program “running into” a null wall.
This FC0-U61 practice question tests your understanding of software development concepts. 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.
Refer to the exhibit. ``` Error: NullReferenceException at line 45 in Calculate.cs ```
A developer sees the above error message. What type of error is this?
Refer to the exhibit. ``` Error: NullReferenceException at line 45 in Calculate.cs ```
Syntax error
Why wrong: Syntax errors are caught by the compiler before execution.
Compile error
Why wrong: Compile errors prevent the program from compiling.
Logic error
Why wrong: Logic errors do not throw exceptions; they produce incorrect output.
Runtime error
NullReferenceException occurs at runtime when an object is null.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Runtime error
The correct answer is C: Runtime error. NullReferenceException occurs during program execution when trying to access an object that is null. Syntax errors (A) are caught at compile time. Compile errors (B) prevent compilation. Logic errors (D) produce wrong results but no exception.
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.
Syntax error
Why it's wrong here
Syntax errors are caught by the compiler before execution.
Compile error
Why it's wrong here
Compile errors prevent the program from compiling.
Logic error
Why it's wrong here
Logic errors do not throw exceptions; they produce incorrect output.
Runtime error
Why this is correct
NullReferenceException occurs at runtime when an object is null.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Command / output trap
Logic errors do not throw exceptions; they produce incorrect output.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the FC0-U61 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which FC0-U61 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Software Development Concepts — This question tests Software Development Concepts — Read the scenario before looking for a memorised answer..
The correct answer is: Runtime error — The correct answer is C: Runtime error. NullReferenceException occurs during program execution when trying to access an object that is null. Syntax errors (A) are caught at compile time. Compile errors (B) prevent compilation. Logic errors (D) produce wrong results but no exception.
Identify which FC0-U61 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This FC0-U61 practice question is part of Courseiva's free CompTIA 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 FC0-U61 exam.
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