5. Let FUNC be the following lisp function: (DEFUN FUNC (L) COND (NULL L) NIL) ((NULL (CDR L)) (CAR L)) (T (FUNC (CDR L)) The NULL function returns a true value if its argument is an empty list. (a) What does the function return when passed (A B) as its argument? (b) What does the function return when passed (A (B C)) as its argument? (c) What does the function return when passed (A B (C)) as its argument? (d) in general, What does the function return when passed a list L