Physics' Concept - 6

Consider two balls A,B. Assume that B is at rest and A is moving towards B. Eventually , after sometime , A collides with B and at this instant A stops and B starts moving with some velocity.Taking this scenario into consideration , what can you say about the statement below :

"After collision , since A stops completely , by law of conservation of energy , the total energy lost by A is now completely gained by B which makes it move."

Note: This is a non-elastic collision.