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_6, if x_6 makes tea, then x_6 is an office clerk. For all x_6, if x_6 were an office clerk, then x_6 is not drinking water. For all x_6, x_6 will make tea if and only if x_6 will cook. For all x_6, x_6 will drink water.
For all x_6, x_6 is not an office clerk can be inferred via the universal modus tollens rule. For all x_6, if x_6 makes tea, then x_6 is cooking can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 cooks, then x_6 is making tea can be inferred via the universal biconditional elimination rule.