In which of the following conditions can you make a U-turn?

• Anytime, without checking for other traffic.
• Only if there are no other vehicles present.
• When you get permission to proceed by a green arrow left-turn signal, but only after you yield to other traffic.
  Explanation:

  "Unless signs tell you otherwise, you can make a U-turn when you get permission to proceed by a green arrow left-turn traffic signal, provided it is allowed and you yield to other traffic."
• Only if there is a sign specifically allowing U-turns at the intersection.