Body A of mass 4m moving with speed u collides with another body B of mass 2m, at rest. The collision is head on and elastic in nature. After the collision the fraction of energy lost by the colliding body A is :

Question

( A ) $\frac{8}{9}$
( B ) $\frac{5}{9}$
( C ) $\frac{1}{9}$
( D ) $\frac{4}{9}$