Which one of the following sentences uses colons incorrectly​? A. ​Susan's desk​ contained: old love​ letters, a​ diary, and five​ dried-up ballpoint pens. B. Hedy found the secret to a lasting​ marriage: honesty. C. I have a great job for​ you: editing my new book. D. ​You'll never guess who was at the company​ picnic: Jerry​ Seinfeld!