Before moving left to pass another vehicle, you should:

Correct answer: C – Check that the lane is clear and signal the lane change
Before passing, check that there is enough clear roadway and that the passing lane is free of traffic. Use the appropriate turn signal before moving into that lane. After passing and becoming safely clear of the other vehicle, signal again before returning to your original lane.
Source: Massachusetts Driver’s Manual — Ch. 4, “Passing”

