What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_4, x_4 will read a book if and only if x_4 will cook. Karen is a nurse. David is cooking or Karen is not a nurse.
If Karen were a nurse, then David is cooking. For all x_4, if x_4 reads a book, then x_4 is cooking. For all x_4, if x_4 cooks, then x_4 is reading a book.