As shown in the picture, a ball of mass m, suspended on the end of a wire, is released from height h and collides elastically, when it is at its lowest point, with a block of mass 2m at rest on a frictionless surface. After the collision, the ball rises to a final height equal to A. 1/9 h B. 1/8 h C. 1/3 h D. 1/2 h E. 2/3 h