If r represents the radius of the orbit of a satellite of mass m moving around a planet of mass M, the velocity of the satellite is given by

Q: If r represents the radius of the orbit of a satellite of mass m moving around a planet of mass M, the velocity of the satellite is given by

(a) $v^2 = \frac{g M}{r}$

(b) $v^2 = \frac{G M m}{r}$

(c) $ v = \frac{G M}{r}$

(d) $v^2 = \frac{G M}{r}$