Block A, with a Mass of 2

Multiple Choice

Block A, with a mass of 2.0 kg, moves along the x axis with a velocity of 5.0 m/s in the positive x direction. It suffers an elastic collision with block B, initially at rest, and the blocks leave the collision along the x axis. If B is much more massive than A, the velocity of A after the collision is:

A) 0
B) +5.0 m/s
C) -5.0 m/s
D) +10 m/s
E) -10 m/s