The correct option is A 70
Deviation is the number by which the given number exceeds the base or is less than the base.
When we take 75 as base, the deviation is 75 – 70 = 5
When we take 80 as base, the deviation is 75 – 80 = -5
So, when we take 90 as base, the deviation is 75 – 90 = -15
Hence, option is A correct.