[单选题]
Consider a small satellite moving in) 2wrmmrmv b sv 6+,bno;wu(wx 0u-dx9 a circular orbit (radius r) about fjy;p0u ru)9ma spherical planet (mass M). Whicrm j9u;0 )fupyh expression gives this satellite's orbital velocity?
A. $v = GM/r$
B. $\sqrt{GM/r}$
C. $GM/r^2$
D. $\sqrt{GM/r^2}$
