A Red Ball with a Velocity of +3

Multiple Choice

A red ball with a velocity of +3.0 m/s collides head-on with a yellow ball of equal mass moving with a velocity of -2.0 m/s. What is the velocity of the red ball after the collision?

A) zero
B) -2.0 m/s
C) +3.0 m/s
D) +2.5.0 m/s
E) +5.0 m/s