Which sentence correctly uses a colon to introduce an explanation?

Which sentence correctly uses a colon to introduce an explanation?

• A. She had one habit: always arriving early.
• B. She had one habit: always arriving early.
• C. She had one habit - always arriving early.
• D. She had one habit, always arriving early.

Answer: (B)

Using a colon to introduce an explanation means the first part is a complete statement, and what follows after the colon sharpens or clarifies exactly what that statement means. Here, “She had one habit” is a complete sentence, and “always arriving early” explains what that habit is. The colon signals that the second part elaborates on the first. The other forms try to connect the idea with a dash or a comma, but they don’t provide that clear, formal explanation that a colon supplies. A dash can be used for emphasis, and a comma here doesn’t mark an explanation in the same way, so they don’t meet the criterion of colon usage for introducing an explanation.

Using a colon to introduce an explanation means the first part is a complete statement, and what follows after the colon sharpens or clarifies exactly what that statement means. Here, “She had one habit” is a complete sentence, and “always arriving early” explains what that habit is. The colon signals that the second part elaborates on the first.

The other forms try to connect the idea with a dash or a comma, but they don’t provide that clear, formal explanation that a colon supplies. A dash can be used for emphasis, and a comma here doesn’t mark an explanation in the same way, so they don’t meet the criterion of colon usage for introducing an explanation.