A particle of mass m is moving in a horizontal circle of radius r under a centripetal force equal to –K/r2, where K is a constant. The total energy of the particle is

(1) $\frac{K}{2r}$

(2) $-\frac{K}{2r}$

(3) $-\frac{K}{r}$

(4) $\frac{K}{r}$