A ball projected from ground at an angle of 45∘ just clears a wall in front. If point of projection is 4 m from the foot of wall and ball strikes the ground at a distance of 6 m on the other side of the wall, the height of the wall is :
(a) 4.4m
(b) 2.4m
(c) 3.6m
(d) 1.6m