n identical cubes each of mass 'm' and side 'l' are on the horizontal surface. Then the minimum amount of work done to arrange them one on the other is

n identical cubes each of mass 'm' and side 'l' are on the horizontal

1.	n identical cubes each of mass 'm' and side 'l' are on the horizontal surface. Then the minimum amount of work done to arrange them one on the other is
Answer» NMGL `(mgl N^(2))/(2)` `(MGLN(n-1))/(2)` `(mgl n(n+1))/(2)` Answer :C