Can anyone please explain me the scoring policy for this question ??

The scoring policy for this question is stated as |w-k|/k. But in the question we were asked to find the least difference between the number of different submatrices in genome and number K which seems to be contradicting with scoring policy

For the given question genome is most stable if w=k, but if w=k the score we get to be zero which sounds to be odd

Thank You…