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_2, if x_2 were a doctor, then x_2 is making tea. Mary is making tea. For all x_2, if x_2 makes tea, then x_2 is a doctor.
There is at least one x for which x will make tea can be inferred via the existential generalization rule. For all x_2, x_2 is a doctor if and only if x_2 will make tea can be inferred via the universal biconditional introduction rule. For all x_2, x_2 will make tea if and only if x_2 is a doctor can be inferred via the universal biconditional introduction rule.