A particle of mass m is moving in a circular path of constant radius 'r'. Such that the centripetal acceleration $a_c$ is varying with time as $a_c=k^2rt$ where R is a constant. What is the power on the particle

Question

$$(a)\;2 \pi mk^2r^2t\quad (b)\;mk^2r^2t \quad (c)\; \frac{mk^4r^2t}{3} \quad (d)\;zero$$