Answer: C) I already heard the news about Jamie and Alex: they are going to have a baby!
Explanation: The first word in a sentence or phrase that is introduced by a colon ( : ) needs to be capitalized as long as what comes after the colon is an independent clause (i.e., a phrase that can stand on its own as a sentence). In this case "they are going to have a baby!" is independent, therefore it should have been capitalized.
