Which sentence correctly uses a colon to denote a list or enumeration?
A. Each group will have members fill the following roles: leader, note-taker, and time-keeper.
B. Our toughest monthly sales goals are in: January, July, and August.
C. Marketing, distribution, and customer service: are the focus areas for 2017.
D. The company will be opening two new offices in: Harrisburg and Reading.
