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 doctor if and only if x_7 is an office clerk. Richard is rich or Susan is a doctor. If Richard were rich, then Susan is an office clerk.
If Susan were a writer, then Richard is rich. For all x_7, if x_7 were a doctor, then x_7 is an office clerk. For all x_7, if x_7 were an office clerk, then x_7 is a doctor.