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_4, x_4 is not bored or x_4 is a sailor. For all x_4, x_4 is bored or x_4 will take a plane. For all x_4, x_4 will not take a plane or x_4 will drink water. For all x_4, x_4 is not a sailor.
For all x_4, x_4 will take a plane or x_4 is a sailor can be inferred via the universal resolution rule.