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, if x_5 were a politician, then x_5 is making tea. For all x_5, x_5 is not a politician. For all x_5, if x_5 makes tea, then x_5 is a politician. For all x_5, x_5 will make tea or x_5 will play tennis.
For all x_5, x_5 will not make tea can be inferred via the universal modus tollens rule. For all x_5, x_5 is a politician if and only if x_5 will make tea can be inferred via the universal biconditional introduction rule. For all x_5, x_5 will make tea if and only if x_5 is a politician can be inferred via the universal biconditional introduction rule.