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_2, if x_2 drives a car, then x_2 is climbing a mountain. For all x_2, if x_2 drives a car, then x_2 is an artist. For all x_2, if x_2 climbs a mountain, then x_2 is driving a car. For all x_2, if x_2 were an artist, then x_2 is driving a car. There is at least one x_2 for which x_2 is an artist or x_2 will climb a mountain.
For all x_2, if x_2 climbs a mountain, then x_2 is an artist can be inferred via the universal transitivity rule. For all x_2, if x_2 were an artist, then x_2 is climbing a mountain can be inferred via the universal transitivity rule. There is at least one x_2 for which x_2 will drive a car can be inferred via the existential disjunction elimination rule. For all x_2, x_2 will drive a car if and only if x_2 will climb a mountain can be inferred via the universal biconditional introduction rule. For all x_2, x_2 will drive a car if and only if x_2 is an artist can be inferred via the universal biconditional introduction rule. For all x_2, x_2 will climb a mountain if and only if x_2 will drive a car can be inferred via the universal biconditional introduction rule. For all x_2, x_2 is an artist if and only if x_2 will drive a car can be inferred via the universal biconditional introduction rule.