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 an electrician, then x_7 is reading a book. For all x_7, x_7 will climb a mountain if and only if x_7 will read a book. There is at least one x_7 for which x_7 is a lawyer. For all x_7, x_7 is an electrician or x_7 will climb a mountain.
For all x_7, if x_7 climbs a mountain, then x_7 is reading a book can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 reads a book, then x_7 is climbing a mountain can be inferred via the universal biconditional elimination rule.