Which sentence uses the colon to introduce an explanation after a complete sentence?

Which sentence uses the colon to introduce an explanation after a complete sentence?

• A. He had a reason: to prove her point.
• B. He had a reason: prove her point.
• C. He had a reason; to prove her point.
• D. He had a reason: Finish the project on time.

Answer: (A)

The key idea is that a colon can introduce an explanation or clarification for what was just stated, following a complete sentence. Here, the part before the colon—“He had a reason”—is a complete thought, and the part after the colon—“to prove her point”—explains what that reason is. It shows the purpose behind the reason in a natural, direct way. The other options don’t fit as well. One option places a short verb phrase after the colon that doesn’t clearly function as an explanation. Another option uses a semicolon instead of a colon, which is a different punctuation rule. The last option uses an imperative, which changes the tone to a command rather than elaborating on the reason.

The key idea is that a colon can introduce an explanation or clarification for what was just stated, following a complete sentence. Here, the part before the colon—“He had a reason”—is a complete thought, and the part after the colon—“to prove her point”—explains what that reason is. It shows the purpose behind the reason in a natural, direct way.

The other options don’t fit as well. One option places a short verb phrase after the colon that doesn’t clearly function as an explanation. Another option uses a semicolon instead of a colon, which is a different punctuation rule. The last option uses an imperative, which changes the tone to a command rather than elaborating on the reason.