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, if x_4 were a server, then x_4 is a carpenter. For all x_4, if x_4 were a carpenter, then x_4 is a server. For all x_4, if x_4 works, then x_4 is a carpenter. There is at least one x_4 for which x_4 is not a server.
There is at least one x_4 for which x_4 is not a carpenter. For all x_4, if x_4 works, then x_4 is a server. For all x_4, x_4 is a server if and only if x_4 is a carpenter. For all x_4, x_4 is a carpenter if and only if x_4 is a server.