What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is cloudy if and only if Karen is playing squash. Karen is playing squash if and only if Charles is climbing a mountain. Charles is not climbing a mountain.
If it is cloudy, then Karen is playing squash. If Karen plays squash, then Charles is climbing a mountain. If Karen plays squash, then it is cloudy. If Charles climbs a mountain, then Karen is playing squash. Karen is not playing squash.