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 James is a writer. If James were a writer, then Susan is listening to a song. If Susan listens to a song, then James is a writer.
James is a writer if and only if Susan is listening to a song. Susan is listening to a song if and only if James is a writer. If it is windy, then James is a writer. If James were a writer, then it is windy.