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_7, if x_7 were sad, then x_7 is rich. There is at least one x_7 for which if x_7 were rich, then x_7 is reading a book. For all x_7, x_7 is not bored. For all x_7, if x_7 reads a book, then x_7 is bored.
For all x_7, x_7 will not read a book can be inferred via the universal modus tollens rule. There is at least one x_7 for which if x_7 were rich, then x_7 is bored can be inferred via the existential transitivity rule. There is at least one x_7 for which if x_7 were sad, then x_7 is reading a book can be inferred via the existential transitivity rule.