Which of the following is an indicator of a code smell?

• A. Long methods
• B. Comprehensive unit tests
• C. Clear module boundaries
• D. Strong type safety

Answer: (A)

A code smell is a hint that there may be maintainability problems in the code, not a bug itself. Long methods are a classic indicator because they usually try to do too many things at once. When a method becomes lengthy, it’s harder to read, understand, and modify, which increases cognitive load and the chance of introducing mistakes. Splitting a long method into smaller, well-named pieces helps clarify intent, makes testing easier, and aligns with the principle of single responsibility.

Comprehensive unit tests are a strong practice that improves reliability, not a smell. Clear module boundaries reflect good design and encapsulation, not a problem. Strong type safety enhances reliability and readability, also not a problem. So the best indicator among these is the presence of long methods.