An Ideal Gas Is Slowly Expanding to Twice Its Original $\sqrt { 2 }$

Multiple Choice

An ideal gas is slowly expanding to twice its original volume with no change in temperature. The average speed of the molecules in the sample is

A) increasing by a factor of 2.
B) increasing by a factor of $\sqrt { 2 }$
C) staying unchanged.
D) decreasing by a factor of $\sqrt { 2 }$
E) decreasing by a factor of 2.