With no explanation, chose the best option from "A" or "B". Alex can get a better job at his company if he tells his boss that his colleague made a mistake and lost a major client. Alex has to decide whether to ruin his colleague's chances for promotion.

A: Alex doubles his efforts at work, improving his own performance, but he doesn't say anything about the shortcomings of his colleague.
B: Alex meets with his boss and tells him that it was his colleague's mistake that cost the company a large client.
A.