Two Bodies a and B Move Toward Each Other with Speeds

Multiple Choice

Two bodies A and B move toward each other with speeds of 80 cm/s and 20 cm/s,respectively.The mass of A is 140 g and that of B is 60 g.After a head-on,perfectly elastic collision,the speed of B is

A) 8.0 cm/s
B) 20 cm/s
C) 92 cm/s
D) 1.2 m/s
E) 1.3 m/s