Why, According to the Popular Argument Discussed by Rachels, Should

Why, according to the popular argument discussed by Rachels, should we reject ethical egoism?

A) because it would be best for Rachels if the rest of us reject ethical egoism
B) because it is implausible that each of us is ultimately motivated solely by self-interest
C) because it is impossible to consistently desire that each person acts in his or her own self-interest
D) because ethical egoism involves the logical error of believing that what is good for someone else must be bad for me