In the pulley system shown the two upper pulleys are fastened together to form single unit. The cable is wrapped around the smaller pulley with its end secured to the pulleys so that it cannot slip. Determine the upward acceleration of block B if A has downward acceleration of `2 m//s^(2)` :
A. `16 m//s^(2)`
B. `8 m//s^(2)`
C. `0.5 m//s^(2)`
D. `0.25 m//s^(2)`
