A Stationary 4-Kg Shell Explodes into Three Pieces

Multiple Choice

A stationary 4-kg shell explodes into three pieces. Two of the fragments have a mass of 1 kg each and move along the paths shown with a speed of 10 m/s. The third fragment moves upward as shown.
-What is the speed of the center of mass of this system after the explosion?

A) zero m/s
B) 1 m/s
C) 3 m/s
D) 5 m/s
E) 7 m/s