A particle starting from rest has a constant acceleration of `4 m//s^2` for `4` seconds. It them retards uniformly for next `8` seconds and comes to rest. Average acceleration during the motion of the particle is.

Options

A. `4 m//s^2`
B. zero
C. `8 m//s^2`
D. `- 4 m//s^2`

Answer

B