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