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_5, x_5 will play tennis or x_5 will drive a car. For all x_5, if x_5 takes a plane, then x_5 is driving a car. There is at least one x_5 for which if x_5 plays tennis, then x_5 is taking a plane. For all x_5, if x_5 drives a car, then x_5 is taking a plane.
There is at least one x_5 for which if x_5 plays tennis, then x_5 is driving a car can be inferred via the existential transitivity rule. There is at least one x_5 for which x_5 will take a plane can be inferred via the existential disjunction elimination rule. For all x_5, x_5 will take a plane if and only if x_5 will drive a car can be inferred via the universal biconditional introduction rule. For all x_5, x_5 will drive a car if and only if x_5 will take a plane can be inferred via the universal biconditional introduction rule.