Question: a. How many one-to-one functions are there from a set with three elements to a set with four elements?
b. How many one-to-one functions are there from a set with three elements to a set with two elements?
c. How many one-to-one functions are there from a set with three elements to a set with three elements?
d. How many one-to-one functions are there from a set with three elements to a set with five elements?
e. How many one-to-one functions are there from a set with m elements to a set with n elements, where m ≤ n?