Which of the following is most likely to act as a base rather than a nucleophile?

Question

Quizplus · Accepted Answer

A molecule or ion acts as a base if it is more likely to accept a proton rather than donate one. In this case, we need to look for a functional group or atom that can stabilize the positive charge after accepting a proton. The most likely candidate is the lone pair on nitrogen in choice C, which can form a stable ammonium ion. The other choices all contain species that are more likely to act as nucleophiles because they have available lone pairs that can attack an electrophile.

Which of the Following Is Most Likely to Act as a Base