Is it E?

May be wrong, though.

For the greatest value of x (and also greatest value of sum of digits), k=1.

x= 5*10^27- 27*10^5 = (10^5) *(5*10^22 - 27)

The decimal notation should be 4(twenty 9s)7300000.

Hence sum of digits is 4 + 180 + 10 =

194
Similarly, for the smallest positive value of x (not looking for negative; assuming that we are looking for the smallest positive value, else it would be infinity)

k=5

x= 5*10^27- 27*10^25 = (10^25) *(500 - 27) = 473(twenty five 0s)

Hence sum of digits is 14.

Hence the difference S-s=180 => Answer E.