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: David is a politician or Karen is not taking a plane. If David were a politician, then John is listening to a song. Karen is taking a plane or Linda is an office clerk. It is overcast or Linda is not an office clerk. If John listens to a song, then it is overcast.
If David were a politician, then it is overcast can be inferred via the transitivity rule. If Karen takes a plane, then David is a politician can be inferred via the rewriting rule. If Linda were an office clerk, then it is overcast can be inferred via the rewriting rule.