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 y, y will make tea if and only if y is a writer. For all y, if y drives a car, then y is a writer. For all y, y will not make tea. For all y, if y were a writer, then y is driving a car.
For all y, y will drive a car if and only if y is a writer can be inferred via the universal biconditional introduction rule. For all y, y is a writer if and only if y will drive a car can be inferred via the universal biconditional introduction rule. For all y, if y makes tea, then y is a writer can be inferred via the universal biconditional elimination rule. For all y, if y were a writer, then y is making tea can be inferred via the universal biconditional elimination rule. For all y, y is not a writer can be inferred via the universal biconditional elimination rule.