A 100 Kg Mass, Initially at Rest, Is Blown Apart

Multiple Choice

A 100 kg mass, initially at rest, is blown apart into a 90.0 kg piece and a 10.0 kg piece. After the blast, the two masses are moving apart with a relative velocity of 100 m/s. The speed of the 10.0 kg mass after the explosion is 90.0 m/s. The total kinetic energy of the two masses after the explosion is

A) 63,200 J.
B) 45,000 J.
C) 30,400 J.
D) 23,400 J.
E) 4,500 J.