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 an artist. For all x_5, x_5 will play tennis if and only if x_5 is a janitor. There is at least one x_5 for which if x_5 were an artist, then x_5 is a janitor.
There is at least one x_5 for which x_5 is a janitor can be inferred via the existential modus ponens rule. For all x_5, if x_5 plays tennis, then x_5 is a janitor can be inferred via the universal biconditional elimination rule. For all x_5, if x_5 were a janitor, then x_5 is playing tennis can be inferred via the universal biconditional elimination rule.