9. For two positive integers m n , let A be a set with m elements (IA - m) and B a set of n elements (Al = n). For each of the following sets, give upper and lower bounds on their cardinality n upper bound states the maximum possible elements in the set. A lower bound states the minimum possibles elements in the set Explain your answer. (a) AnB (b) AUB (c) A \ B (d) B\A