A unidirectional force F varying with time t as shown in the fig. acts on a body initially at rest for a short duration 2T. Then the velocity acquired by the body is

• A

  $\frac{{\mathrm{\pi F}}_0\mathrm{T}}{4m}$

• B

  $\frac{{\mathrm{\pi F}}_{0\mathrm{T}}}{2m}$

• C

  $\frac{F_{0}T}{4m}$

• D

  zero