The Temperature of a Room at 10 ^$\circ$ C Is Raised to 30

The temperature of a room at 10 ^$\circ$ C is raised to 30 ^$\circ$ C.What is the percent increase in the average speed of the molecules?

A) 7.1 %
B) 2.3 %
C) 3.4 %
D) 10 %
E) 1.5 %