What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_6, if x_6 were a server, then x_6 is not a doctor. For all x_6, x_6 is a doctor. For all x_6, x_6 is a server or x_6 is an office clerk. For all x_6, if x_6 were a mechanic, then x_6 is not an office clerk.
For all x_6, x_6 is not a server.