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_9, x_9 will not listen to a song. For all x_9, x_9 is rich if and only if x_9 is bored. For all x_9, if x_9 were bored, then x_9 is listening to a song. For all x_9, x_9 is rich or x_9 will read a book.
For all x_9, x_9 is not bored can be inferred via the universal modus tollens rule. For all x_9, if x_9 were rich, then x_9 is bored can be inferred via the universal biconditional elimination rule. For all x_9, if x_9 were bored, then x_9 is rich can be inferred via the universal biconditional elimination rule.