Let A={o,p,q,r,s}. a. How many subsets does A have? b. How many proper subsets does A have? c. How many subsets does A have that include the elements o and p? a. A has subsets. (Type a whole number.) b. A has proper subsets. (Type a whole number.) c. A has subsets that include the elements o and p. (Type a whole number.)