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