The first one is B because its subtracting one
The second one is B because it would be the opposite reciprocal of 5/3 (-3/5)
Remember, the number of subsets of a set is 2

, where n is the number of elements in the set. Thus, it is 2³ = 8. If you want a proof for that, ask in comments below.
here, it's not clear , but visible
Http://ncert.nic.in/ncerts/l/gemp109.pdf
see if it helps if not I am sorry