Daisy (50 Kg Mass) Skates on Ice at 4

Daisy (50. kg mass) skates on ice at 4.0 m/s to greet her friend (70. kg mass) , who is standing still, with open arms. As they collide, while holding each other, with what speed do they both move off together?

A) zero
B) 2.5 m/s
C) 5.0 m/s
D) 1.7 m/s