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 Mary is a nurse. For all x_10, if x_10 were a mechanic, then x_10 is a nurse. It is not raining.
If it rains, then Mary is a nurse. If Mary were a nurse, then it is raining. Mary is not a nurse.