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_6, x_6 will not climb a mountain. For all x_6, x_6 is not a sailor or x_6 is sad. For all x_6, if x_6 were a police officer, then x_6 is climbing a mountain. There is at least one x_6 for which x_6 is a sailor or x_6 is a police officer.
For all x_6, x_6 is not a police officer can be inferred via the universal modus tollens rule. There is at least one x_6 for which x_6 is a police officer or x_6 is sad can be inferred via the existential resolution rule.