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: There is at least one x_9 for which if x_9 were a lawyer, then x_9 is driving a car. For all x_9, if x_9 makes tea, then x_9 is a lawyer. For all x_9, x_9 will make tea if and only if x_9 is a server.
There is at least one x_9 for which if x_9 makes tea, then x_9 is driving a car can be inferred via the existential transitivity rule. For all x_9, if x_9 makes tea, then x_9 is a server can be inferred via the universal biconditional elimination rule. For all x_9, if x_9 were a server, then x_9 is making tea can be inferred via the universal biconditional elimination rule.