The Root-Mean-Square Speed of the Molecules of an Ideal Gas $\sqrt { 2 }$

The root-mean-square speed of the molecules of an ideal gas is v.The gas is now slowly compressed to one-half its original volume with no change in temperature.What is the root-mean-square speed of the molecules now?

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