What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is windy if and only if Charles is taking a plane. Charles is not taking a plane. If Patricia were an office clerk, then it is windy. Barbara is rich if and only if Patricia is an office clerk.
If it is windy, then Charles is taking a plane. If Barbara were rich, then Patricia is an office clerk. If Charles takes a plane, then it is windy. If Patricia were an office clerk, then Barbara is rich. It is not windy.