Give regular expressions (using = {a, b}, , and the operators , , * ) for the following subsets of {a, b}*.

a) A = { w | w is in ^* and w begins with bb and ends with aa }

b) B = { w | w is in ^* and w has an odd number of bs}

c) C = { w | w is in ^* and w has an even number of as and an even number of bs}