Let A be a regular language and B a non-regular language. The following is true: AB is always nonregular AB is always regular AB is always finite AB is always infinite None of the above. Let L be denoted by the regular expression (aa+ab+ba+bb)aa(aa+ab+ba+bb) Which of the following strings is not in L ? abbaabaa is not in L abbaabbaab is not in L aabbbabb is not in L baabaaba is not in L bbbaaabb is not in L abbaabaa is not in L All of the above strings are in L