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_12, x_12 is a carpenter and x_12 is a mechanic. There is at least one x_12 for which if x_12 drives a car, then x_12 is a taxi driver. For all x_12, x_12 will drive a car or x_12 will cook. For all x_12, if x_12 cooks, then x_12 is a taxi driver.
For all x_12, x_12 is a carpenter can be inferred via the universal simplification rule. For all x_12, x_12 is a mechanic can be inferred via the universal simplification rule. There is at least one x_12 for which x_12 is a taxi driver can be inferred via the existential disjunction elimination rule.