Consider the following premises. If Joseph drives a car, then it is not sunny. Susan is listening to a song if and only if Joseph is driving a car. Susan is listening to a song if and only if Thomas is climbing a mountain. It is sunny. Can we infer the following from them? If we can, name the inference rule being used: Thomas is climbing a mountain.
 From the fact that if Joseph drives a car, then it is not sunny, and that it is sunny we can infer that Joseph is not driving a car via modus tollens. From the fact that Susan is listening to a song if and only if Joseph is driving a car, and that Joseph is not driving a car we can infer that Susan is not listening to a song via biconditional elimination. Finally, from the fact that Susan is listening to a song if and only if Thomas is climbing a mountain, and that Susan is not listening to a song we can infer that Thomas is not climbing a mountain via biconditional elimination, which contradicts that Thomas is climbing a mountain. Therefore, the answer is no.