A block B is suspended from a cable that is attached to the block at E, wraps around three pulleys and is tied to the back of a truck D. Ifthe tmck starts from rest when `x_(D)` is zero and moves forward with a constant acceleration of `a_(P)=3//2 m//s^(2)`, if the speed of the block at the instant `x_(D)=3 m` is :
A. `1/5 m//s`
B. `2/5 m//s`
C. `3/5 m//s`
D. `1 m//s`
