Well, to be technically precise about it, none of the choices is a correct answer.
Two hours after starting out, the car is 200 km south of where it started.
Its displacement is 200 km south.
Its average velocity is (200 km south) / (2 hours)
Velocity = 100 km/hour South
None of the choices has the correct units, and none has a direction. So none of the choices can even be a 'velocity'.