What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z_4, z_4 is an office clerk. Richard is a server if and only if Sarah is an electrician. Richard is a server if and only if it is snowing. Sarah is not an electrician.
If Richard were a server, then Sarah is an electrician. If Richard were a server, then it is snowing. If Sarah were an electrician, then Richard is a server. If it snows, then Richard is a server. Richard is not a server.