A small block of wood of relative density 0.5 is submerged at a depth of 1.2 m in a vessel filled with water. The vessel is made to accelerate upward with an acceleration of 5 m/s2 and the block is released. Time taken by block to reach the surface is : (g=10 m/s2)
(A) 0.6 sec
(B) 0.4 sec
(C) 1.2 sec
(D) 1 sec