Here the cell (S4,D3) is the last simultaneously
satisfied positive allocated cell and D3 and D4 are
only uncrossed out columns with zero demand. In
that case if we allocate zero demand by LCM then
cell (S3,D3) is the least cost cell with cost 6 between
D3 and D4 and zero demand should be allocate in
that (S3,D3) cell and hence one zero demand is
remains which must be leave from calculation by the
rules of TP algorithm. So the final feasible solution
by LCM is given below