Which one of the following sentences contains an unnecessary colon?
a. Carlos has three goals in life: to graduate from college, own his own home, and work in the computer industry.
b. I wrote my shopping list and put: milk, soup, chicken, and ice cream on it.
c. Here's the question on all of our minds: Will our team be able to defeat their arch rivals tonight?
d. She wants one thing: a new job.