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_9, if x_9 were a lawyer, then x_9 is making tea. For all x_9, if x_9 makes tea, then x_9 is sleeping. There is at least one x_9 for which x_9 will not sleep. For all x_9, if x_9 makes tea, then x_9 is a lawyer.
There is at least one x_9 for which x_9 will not make tea can be inferred via the existential modus tollens rule. For all x_9, if x_9 were a lawyer, then x_9 is sleeping can be inferred via the universal transitivity rule. For all x_9, x_9 is a lawyer if and only if x_9 will make tea can be inferred via the universal biconditional introduction rule. For all x_9, x_9 will make tea if and only if x_9 is a lawyer can be inferred via the universal biconditional introduction rule.