Arrange the summation expressions in increasing order of their values

Sum of n terms  = a1  (r^n-1/ (r-1)

Sum of first one = 3 * (4^5 - 1) / 3  =  1023
  ..           2nd =  5 * (6^2 - 1) / 5 =  35
   ..            3rd = 5 ^4 - 1 / 4 =  156
   ..            4th =  4 * (5^4 - 1) / 4 = 624

So in increasing order its   2nd, 3rd, 4th and first.