What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Mary is a sailor or Joseph is not a writer. Mary is a sailor if and only if Jennifer is playing tennis. Jennifer is playing tennis if and only if Joseph is a writer.
If Joseph were a writer, then Mary is a sailor. If Mary were a sailor, then Jennifer is playing tennis. If Jennifer plays tennis, then Joseph is a writer. If Jennifer plays tennis, then Mary is a sailor. If Joseph were a writer, then Jennifer is playing tennis.