Which statement best captures the primary role of a topic sentence?

• A. State the main idea and guide the paragraph.
• B. Explain every detail.
• C. List examples.
• D. Pose a question.

Answer: (A)

The main idea of a topic sentence is to state the paragraph's central idea and guide its development. It signals to the reader what the paragraph will be about and sets the scope, so the sentences that follow stay focused on supporting that idea. It also helps connect the paragraph to the larger argument by framing the point that will be elaborated. Explaining every detail or merely listing examples aren’t the primary roles, since details and examples come after the main idea is stated. Posing a question might be a stylistic choice, but it doesn’t on its own define the paragraph’s guiding purpose.