A car of mass m starts from rest and acquires a velocity along east v = vi(v > 0) in two seconds. Assuming the car moves with uniform acceleration, the force exerted on the car is
(a) (mv/2) eastward and is exerted by the car engine.
(b) (mv/2) eastward and is due to the friction on the tyres exerted by the road.
(c) more than (mv/2)eastward exerted due to the engine and overcomes the friction of the road.
(d) (mv/2) exerted by the engine