Before changing lanes, you should

Answer: A — Look over your shoulder

When changing lanes, you should look over your shoulder to check for any vehicles or objects that may be in your potential path. This is an important precautionary step that can prevent accidents or collisions. Stopping your vehicle (option B) is not necessary as you are still in motion and should only stop when necessary. Accelerating (option C) is incorrect as it does not provide enough time or opportunity to check for potential obstacles. You should also remember to use your turn signal when changing lanes, making option D incorrect.