There's no physics or electronics to this question.
It's just arithmetic.
The last part of the question TELLS you how many 'coulombs per electron'.
If you just flip that fraction (divide ' 1 ' by it, take its reciprocal), then
you'll have 'electrons per coulomb', and 5 of those will answer the question.
I got 31,250,000,000,000,000,000 . I could be wrong. You should check it.