What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_9, x_9 will climb a mountain if and only if x_9 is a doctor. For all x_9, x_9 will climb a mountain if and only if x_9 is a doctor.
For all x_9, if x_9 climbs a mountain, then x_9 is a doctor. For all x_9, if x_9 climbs a mountain, then x_9 is a doctor. For all x_9, if x_9 were a doctor, then x_9 is climbing a mountain. For all x_9, if x_9 were a doctor, then x_9 is climbing a mountain.