What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If John were a writer, then it is windy. If it is sunny, then John is a writer. If it is windy, then it is sunny. John is not a writer.
It is not sunny. If John were a writer, then it is sunny. If it is sunny, then it is windy. If it is windy, then John is a writer.