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_11, x_11 will make tea. For all x_11, x_11 will make tea if and only if x_11 is a janitor. For all x_11, x_11 will work. For all x_11, if x_11 works, then x_11 is a sailor.
For all x_11, x_11 is a sailor can be inferred via the universal modus ponens rule. For all x_11, x_11 will make tea and x_11 will work can be inferred via the universal conjunction rule. For all x_11, x_11 will work and x_11 will make tea can be inferred via the universal conjunction rule. For all x_11, if x_11 makes tea, then x_11 is a janitor can be inferred via the universal biconditional elimination rule. For all x_11, if x_11 were a janitor, then x_11 is making tea can be inferred via the universal biconditional elimination rule.