Problem 4 (20): Give a regular expression for the following languages. (a) A = {w: w has two O's } where E = {0,1} (b) B = {w: w ends in txt" } where E = {a,b,...,Z} (c) C = {w: w starts with aa and ends with any number of zs } where = {a,b,...,Z} (d) D = {w: w is a string representing an even binary number} where E= {0,1}