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_8, if x_8 reads a book, then x_8 is taking a plane. There is at least one x_8 for which x_8 is rich. For all x_8, x_8 will take a plane if and only if x_8 is a lawyer. For all x_8, x_8 will read a book or x_8 is a lawyer.
For all x_8, if x_8 takes a plane, then x_8 is a lawyer can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were a lawyer, then x_8 is taking a plane can be inferred via the universal biconditional elimination rule.