[QA] You must never take your helmet off while you are riding a motor.

Question:

You must never take your helmet off while you are riding a motor.

• A.
  If you are riding a motor, you needn’t wear a helmet.
• B.
  Helmets must be worn at all times when you are riding a motor.
• C.
  When you are riding a motor, wearing a helmet is not a must.
• D.
  You shouldn’t wear a helmet whenever you are riding a motor.