What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all z, if z plays tennis, then z is playing squash. For all z, z is a soldier. There is at least one z for which if z were a cashier, then z is not playing squash. For all z, if z were a soldier, then z is curious. For all z, z will play tennis if and only if z is curious.
For all z, z is curious can be inferred via the universal modus ponens rule. For all z, if z plays tennis, then z is curious can be inferred via the universal biconditional elimination rule. For all z, if z were curious, then z is playing tennis can be inferred via the universal biconditional elimination rule.