Please explain

6. (8 points) Among the following statements, write the letters of all correct (true) statements here: a) If E and Fare regular expressions, then there is a regular expression for the -set of strings in C(E)UC(F) where C gives the set of strings represented by a regular expression. Tra b) For all languages A and B over ., (A"B").-(B"A").. ne erl is a regular language then LU (L.) is also a regular language. (me For every n state nondeterministic finite automaton there is an equiv- alent deterministic finite automaton having at most n states. TA AG) If M is a nondeterministic finite automaton over and every state of M dan accepting state, then L(M) =