3.7. Find a regular expression corresponding to each of the following subsets of la, bl a. The language of all strings containing exactly two a's b. The language of all strings containing at least two a's c. The language of all strings that do not end with ab d. The language of all strings that begin or end with aa or bb e. The language of all strings not containing the substring aa. f. The language of all strings in which the number of a's is even The language of all strings containing no more than one occurrence of the string aa. (The string aaa should be viewed as containing two occurrences of aa.) h. The language of all strings in which every a is followed immediately by bb i. The language of all strings containing both bb and aba as substrings i. The language of all strings not containing the substring aaa k. The language of all strings not containing the substring bba 1. The language of all strings containing both bab and aba as substrings m. The language of all strings in which the number of a's is even and the number of b's is odd