What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_7, x_7 is a server if and only if x_7 is a nurse. For all x_7, x_7 is a nurse if and only if x_7 is a server.
For all x_7, if x_7 were a server, then x_7 is a nurse. For all x_7, if x_7 were a nurse, then x_7 is a server. For all x_7, if x_7 were a nurse, then x_7 is a server. For all x_7, if x_7 were a server, then x_7 is a nurse.