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 were fast, then x_2 is an astronaut. For all x_2, x_2 is a taxi driver or x_2 is a politician. There is at least one x_2 for which if x_2 were a politician, then x_2 is an astronaut. For all x_2, x_2 is not a taxi driver or x_2 is fast.
For all x_2, x_2 is a politician or x_2 is fast can be inferred via the universal resolution rule.