This question illustrates differences and commonalities between NFAs and DFAs. (a) Show that if M is a DFA that recognizes language B, then swapping the accept and nonaccept states in M yields a new DFA M' recognizing the complement of B, B. Which operation does this imply the regular languages are closed under? (b) Prove by counterexample that if M is a NFA that recognizes languages B, then swapping the accept and nonaccept states in M does not necessarily yield an NFA recognizing B. With this in mind, is the class of languages recognized by NFA's closed under complement (explain your answer!)