Let A be the set of English words that contain the letter x, and let B be the set of English words that contain the letter q. Express each of these sets as a combination of A and B.
a) The set of English words that do not contain the letter x.
b) The set of English words that contain both an x and a q.
c) The set of English words that contain an x but not a q.
d) The set of English words that do not contain either an x or a q.
e) The set of English words that contain an x or a q, but not both.