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 t as \[{{a}_{c}}={{k}^{2}}r{{t}^{2}}\] where k is a constant. The power delivered to the particles by the force acting on it is

• A. \[2\pi m{{k}^{2}}{{r}^{2}}t\]
• B. \[m{{k}^{2}}{{r}^{2}}t\]
• C. \[\frac{\left( m{{k}^{4}}{{r}^{2}}{{t}^{5}} \right)}{3}\]
• D. zero