Answer
Finding all possible functions between X and Y is the same as finding all possible combinations between X and Y.
Work Step by Step
The number of combinations can be found using this formula:
Let a be the number of elements in X and let b be the number of elements in Y.
&number of combinations = b^{a}&
So for part (a) we have &2^{2}& which is 4 combinations, part (b) we have &1^{3}& which is 1 combination and then finally part (c) we have &2^{3}& which is 8 combinations.