Two Planets Have the Same Surface Gravity, but Planet B $r \sqrt { 2 }$

Multiple Choice

Two planets have the same surface gravity, but planet B has twice the mass of planet A. If planet A has radius r, what is the radius of planet B?

A) 2r
B) r
C) $r \sqrt { 2 }$
D) 4r
E) $r / \sqrt { 2 }$