[单选题]
Two planets have the o/a 5fxounl: fnh8zg; 33m.(9 gykkmbsame surface gravit5-hpol5y2*ku r ucy,fy, but planet B has twice the radius of planet A. If planet A has mass m, what is th uk, u5crlp2oy-hf5*ye mass of planet B?
A. $0.707 \; m$
B. $m$
C. $1.414 \; m$
D. $4 \; m$
