A Figure Skater on Ice with Arms Extended,spins at a Rate

Multiple Choice

A figure skater on ice with arms extended,spins at a rate of 3.5 rev/s.After he draws his arms in,he spins at 6.0 rev/s.By what factor does the skater's kinetic energy change when he draws his arms in?

A) 2.4
B) 1.7
C) 0.58
D) 0.12