[单选题]
Planet X has half the mass and twice the/,iu-a2 2 *c2fgibvtqgjl+ s n diameter of planet Y. The escape speyf,,dob+y oe 6ed froed fbyy,o6 o+,m the surface of planet X is given by v. What is the escape speed from the surface of planet Y ?
A. $\frac{v}{2}$
B. $\frac{v}{\sqrt{2}}$
C. $v\sqrt{2}$
D. 2v
