A motor is fixed inside a box which is moving upwards with velocity 5 m/s. String is winding at the rate 3 m/s. Then the velocity of block A will be:
(A) 2.5 m/s downwards 2.5 m/s
(B) 5 m/s downwards 5 m/s
(C) 1 m/s downwards 1 m/s
(D) 2 m/s downwards