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_2, z_2 is a server or z_2 is not a musician. For all z_2, z_2 is a server if and only if z_2 will work.
For all z_2, if z_2 were a musician, then z_2 is a server can be inferred via the universal rewriting rule. For all z_2, if z_2 were a server, then z_2 is working can be inferred via the universal biconditional elimination rule. For all z_2, if z_2 works, then z_2 is a server can be inferred via the universal biconditional elimination rule.