A car is moving along a straight road with a uniform acceleration. It passes through two points P and Q separated by a distance with velocity `30km//h` and `40 km//h` respectively. The velocity of the car midway between P and Q is
A. `33.3 km//h`
B. `20sqrt(2)km//h`
C. `25 sqrt(2) km//h`
D. `0.35 km//h`