The Root-Mean-Square Speed of the Molecules of an Ideal Gas $v$

Multiple Choice

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