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