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_7, x_7 will take a plane. There is at least one x_7 for which if x_7 were a nurse, then x_7 is making tea. For all x_7, x_7 will not take a plane or x_7 is a bartender. For all x_7, x_7 is a bartender if and only if x_7 will make tea.
For all x_7, if x_7 were a bartender, then x_7 is making tea can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 makes tea, then x_7 is a bartender can be inferred via the universal biconditional elimination rule.