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 not drive a car. For all y, if y works, then y is a cashier. For all y, if y were a cashier, then y is working. For all y, y will drive a car if and only if y is a cashier.
For all y, y will work if and only if y is a cashier can be inferred via the universal biconditional introduction rule. For all y, y is a cashier if and only if y will work can be inferred via the universal biconditional introduction rule. For all y, if y drives a car, then y is a cashier can be inferred via the universal biconditional elimination rule. For all y, if y were a cashier, then y is driving a car can be inferred via the universal biconditional elimination rule. For all y, y is not a cashier can be inferred via the universal biconditional elimination rule.