What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y, if y were a mechanic, then y is working. William is a bartender if and only if William is a mechanic. For all y, if y works, then y is a bartender.
If William were a bartender, then William is a mechanic. If William were a mechanic, then William is a bartender. For all y, if y were a mechanic, then y is a bartender.