He believes that working with others is a smart business move
The colon is a punctuation mark consisting of two equally sized dots centered on the same vertical line.
The tone and the fact that the narrator says "she'd miss me", drives you to think that the narrator assumes that she will never see Denise again, i.e option D.
Explanation:
intend to convey or refer to (a particular thing); signify.
"I don't know what you mean"