[单选题]
Consider a small satellite mo3myz6s b)lw6jt0p a( 0 vy4jwxving in a circular orbit (radius r) about3-nry5v/h odq a spherical planet (mass M). Which expression gy dv/3rhnq- 5oives this satellite's orbital velocity?
A. $v = GM/r$
B. $\sqrt{GM/r}$
C. $GM/r^2$
D. $\sqrt{GM/r^2}$