Correct Answer - A
Given mass `=2kg`
`x (t) =pt + qt^(2) + rt^(3)`
`v =(dx)/(dt) = p + 2qt + 3rt^(2)`
`a = (dv)/(dt) = 0 + 2q +6rt` ltbr gtat `t =2s, a =2q + 6 xx 2 xx r`
`= 2q +12r`
`= 2 xx 4 + 12 xx 5`
`= 8 + 60 =68 m//s`
Force ` =F =ma`
`=2 xx 68 =136 N` .