[单选题]
Two planets have the same surface gravity, buz;x) pt7e fhc;j+ri9m,we3bit planet B huiz,*p/q r eth :oi0x-as twice the mass of planet A. If planet A hihu-tz: /pqirox0*e, as radius r, what is the radius of planet B?
A. $0.707 \; r$
B. $r$
C. $1.414 \; r$
D. $4 \; r$
