A uniform rod AB of mass m and length l is at rest on a smooth horizontal surface. An impulse J is applied to the end B perpendicular to the rod in the horizontal direction. The speed of particle P at a distance l/6 from the center towards A of the rod after time t = πml/12J is
A. 2J/m
B. J√2/m
C. J/m
D. √2J/m