What is a topic sentence?

• A. The last sentence in a paragraph.
• B. A sentence describing the setting.
• C. A sentence that asks a question.
• D. The first sentence in a paragraph that introduces the main idea of that paragraph

Answer: (D)

The topic sentence states the main idea of the paragraph and usually signals what the paragraph will discuss, serving as a clear guide for the reader. It’s typically placed at the beginning, so as soon as you start reading you know the focus and what kinds of details will follow to support that idea. That makes the paragraph coherent and easy to follow.

The best match says the first sentence in a paragraph introduces the main idea of that paragraph. That alignment—a starting sentence that names the central point—fits how topic sentences function in most writing.

Why the other options don’t fit as the topic sentence: the last sentence in a paragraph is usually the closing sentence that wraps up the idea rather than present it. Describing the setting is a specific descriptive detail, not the paragraph’s central idea. A sentence that asks a question can serve as a hook or a rhetorical device, but it doesn’t by itself present the paragraph’s main idea.