A particle of mass m is moving in a circular path of constant radius r such that its centripetal  acceleration a_c is varying with time to as  a_c= k²rt²  where k is a  constant. What is the power  delivered to the particle by the forces acting

• A

  $m k^2{r}^{2}t$

• B

  $m{k}^2{r}^2\frac{t}{4}$

• C

  $m{k}^2{r}^2\frac{t}{6}$

• D

  $\frac{m{k}^2{r}^{2}t}{8}$