The correct option is C Either c or 0
There should be either 5 or 0 at ones place for a number to be divisible by 5.
Given, c is non zero natural number not more than 5,
i.e. 0 < c ≤ 5
When 23abc is divided by 5,
(i) If c = 1,2,3,4 the remainders are 1,2,3,4 respectively
(ii) If c = 5, the remanider is 0.
Therefore, on dividing 23abc by 5, the remainder will be either c or 0.