What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Barbara is an office clerk or Karen is climbing a mountain. Karen is climbing a mountain if and only if Barbara is a politician. For all z_1, z_1 is an office clerk if and only if z_1 is a politician.
If Karen climbs a mountain, then Barbara is a politician. If Barbara were a politician, then Karen is climbing a mountain. For all z_1, if z_1 were an office clerk, then z_1 is a politician. For all z_1, if z_1 were a politician, then z_1 is an office clerk.