[单选题]
Two planets have thetq(60)*-ty- p7 voncuvicgc d kv:icofs) f1, sk4*hq same surface gravity, but planet B has twice the radius of planet A. If planet A 1o:* h qv4,kicf)ssfkhas mass m, what is the mass of planet B?
A. $0.707 \; m$
B. $m$
C. $1.414 \; m$
D. $4 \; m$
