At this intersection, which vehicles are required to stop?

At this intersection, which vehicles are required to stop?
A)All of them.
B)The red and the blue.
C)The green and the red.Correct
When traffic lights exist only on the left, only those drivers intending to continue straight ahead or turn left must obey their signals. Those intending to turn right must comply with the general right-of-way rule: yield to the right.