C, 80-75=5 and 95-90=5. Meaning your answer would be 5!
The answer to this question is 8/10 which also equals 4/5
F=72
g=6
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Therefore:


But what is e?
E=76
G=32
g=6
And:

Which means that:

If you take this value into account, you will discover that f is...

So I would have to say that the answer is approximately (c).