Two equal masses m, and m, moving along the same straight line with velocities + 3 m/s and -5 m/s respectively collide elastically. Their velocities after the collision will be respectively
 

• A

   + 2 m/s for both

• B

  - 3 m/s and + 5 m/s

• C

   -4m/s and+4mls

• D

   -5 m/sand + 3m/s