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_17, if x_17 were an astronaut, then x_17 is driving a car. For all x_17, if x_17 drives a car, then x_17 is an astronaut. For all x_17, if x_17 were an astronaut, then x_17 is a lawyer. There is at least one x_17 for which x_17 is not a lawyer. For all x_17, x_17 will drive a car or x_17 will take a plane.
There is at least one x_17 for which x_17 is not an astronaut can be inferred via the existential modus tollens rule. For all x_17, if x_17 drives a car, then x_17 is a lawyer can be inferred via the universal transitivity rule. For all x_17, x_17 is an astronaut if and only if x_17 will drive a car can be inferred via the universal biconditional introduction rule. For all x_17, x_17 will drive a car if and only if x_17 is an astronaut can be inferred via the universal biconditional introduction rule.