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 x_5, x_5 is a taxi driver if and only if x_5 will play tennis. For all x_5, x_5 is an electrician. For all x_5, if x_5 were an electrician, then x_5 is playing tennis.
For all x_5, x_5 will play tennis can be inferred via the universal modus ponens rule. For all x_5, if x_5 were a taxi driver, then x_5 is playing tennis can be inferred via the universal biconditional elimination rule. For all x_5, if x_5 plays tennis, then x_5 is a taxi driver can be inferred via the universal biconditional elimination rule.