A particle of mass m is executing oscillations about the origin on the X-axis with amplitude A. Its potential energy is given as \[U(x)=\alpha {{x}^{4}}\] where a is a positive constant. The x coordinate of the particle where the potential energy is one third of the kinetic energy is

• A. \[\pm A/2\]
• B. \[\pm A/\sqrt{2}\]
• C. \[\pm A/3\]
• D. \[\pm A/\sqrt{3}\]