What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is raining if and only if Charles is playing tennis. Charles is not playing tennis. For all x_17, if x_17 plays tennis, then x_17 is a writer. If Charles were a writer, then it is raining.
If it rains, then Charles is playing tennis. If Charles plays tennis, then it is raining.