The bob $A$ of a simple pendulum is released when the string makes an angle of $45^{\circ}$ with the vertical. It hits another bob $B$ of the same material and same mass kept at rest on the table. If the collision is elastic,what happens after the collision?

• A
  Both $A$ and $B$ rise to the same height.
• B
  Both $A$ and $B$ come to rest at $B$.
• C
  Both $A$ and $B$ move with the same velocity of $A$.
• D
  $A$ comes to rest and $B$ moves with the velocity of $A$.