[单选题]
Consider a small satellite moaei7n 7hwo5b4pq9f(kno) b ,.p lbdlu*gbd 8,ving in a circular orbit (radius r) about acxxrjarbz *,tix 698j5xr9,a,u.cz c spherical planet (mass M). Which exp8r6jcjz cxara9rz. ,,c 9 xx, uibx*5tression gives this satellite's orbital velocity?
A. $v = GM/r$
B. $\sqrt{GM/r}$
C. $GM/r^2$
D. $\sqrt{GM/r^2}$
