If X and Y are any sets, which of the following exactly expresses what it means for X ⊆ Y to be false? There is an element in Y that is not in X. No element in X is in Y. There is an element in X that is not in Y. No element in Y is in X. Let A = {n ∈ Z | n = 5r for some integer r} and B = {m ∈ Z | m = 20s for some integer s}. Determine which of the following statements are true and which are false. (Enter TRUE if the statement is true, and enter a number that could be used as the basis for a counterexample if the statement is false). (a) A ⊆ B = (b) B ⊆ A =