The correct option is C 90
The deviation is the number by which the given number exceeds the base or is less than the base.
When we take 70 as base, the deviation is 82 – 70 = 12
When we take 80 as base, the deviation is 82 – 80 = 2
So, when we take 90 as base, the deviation is 82 – 90 = -8
Hence, option C is correct.