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: If Joseph climbs a mountain, then Jessica is an office clerk. If David takes a plane, then Thomas is sleeping. Joseph is climbing a mountain. Jessica is an office clerk or Thomas is not sleeping.
Jessica is an office clerk can be inferred via the modus ponens rule. If Thomas sleeps, then Jessica is an office clerk can be inferred via the rewriting rule.