Correct Answer - B
Till 11 s, acceleration is positive, so velocity will happen at 11 s,
The area under the acceleration - time graph gives change in
velocity. Since particle starts with u = 0, change in velocity is
`V_f - V_i = V_(max) - 0 = Area under a-t graph`
or `v_(max) = 1/2 xx 10 xx 11 = 55 ms^(-1)`.