A uniform metal chain of mass m and length ‘L’ passes over a massless and frictionless pulley. It is released from rest with a part of its length ‘l’ is hanging on one side and rest of its length ‘L – l’ is hanging on the other side of the pulley. At a certain point of time, when l = L/x , the acceleration of the chain is g/2 .The value of x is ………

(A) 6
(B) 2
(C) 1.5
(D) 4