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 y_4, if y_4 climbs a mountain, then y_4 is a police officer. For all y_4, if y_4 writes a letter, then y_4 is climbing a mountain. For all y_4, if y_4 were a police officer, then y_4 is writing a letter. For all y_4, y_4 will write a letter or y_4 is not a police officer.
For all y_4, if y_4 climbs a mountain, then y_4 is writing a letter can be inferred via the universal transitivity rule. For all y_4, if y_4 writes a letter, then y_4 is a police officer can be inferred via the universal transitivity rule. For all y_4, if y_4 were a police officer, then y_4 is climbing a mountain can be inferred via the universal transitivity rule. For all y_4, if y_4 were a police officer, then y_4 is writing a letter can be inferred via the universal rewriting rule.