Please delete this answer.
The number of permutations of the 4 different letters, taken two at a time, is given by:
(x, y)
Domain = x
Range = y
It is a function when none of the x values are repeating.
Answer - C) Both A and B
Hope this helps and makes sense!!
If you take 3.5 and divide it by 0.05, or times 20, that would make it 70.