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: Mary is not listening to a song. For all x, x will drive a car if and only if x will listen to a song. If Mary doesn't drive a car, then Barbara is fast. It is sunny.
Mary is not listening to a song and it is sunny can be inferred via the conjunction rule. It is sunny and Mary is not listening to a song can be inferred via the conjunction rule. For all x, if x drives a car, then x is listening to a song can be inferred via the universal biconditional elimination rule. For all x, if x listens to a song, then x is driving a car can be inferred via the universal biconditional elimination rule.