When changing lanes, you should signal before:

Answer: B — Entering the lane

When changing lanes, it is important to use your turn signal before entering the lane. This lets other drivers know your intention to change lanes and gives them time to adjust their own driving accordingly. Option A is incorrect because you should signal before entering the lane, not when you are exiting it. Option C is incorrect because entering the intersection is a separate action and requires its own signal. Option D is incorrect because signaling is necessary when changing lanes.