Which of the following statements about blind spots is true

Which of the following statements is true?

A. On roads with more than one lane in each direction, do not drive in someone else's blind spot.
B. Before you move sideways to change lanes, turn your head to make sure your blind spots are clear.
C. Blind spots are areas near the left and right rear corners of your vehicle that you cannot see in your rearview mirrors.
D. all of the above