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 Linda were a nurse, then Thomas is climbing a mountain. If James takes a plane, then it is overcast. If it is overcast, then Linda is a nurse. James is taking a plane if and only if Thomas is climbing a mountain.
If James takes a plane, then Linda is a nurse can be inferred via the transitivity rule. If it is overcast, then Thomas is climbing a mountain can be inferred via the transitivity rule. If James takes a plane, then Thomas is climbing a mountain can be inferred via the biconditional elimination rule. If Thomas climbs a mountain, then James is taking a plane can be inferred via the biconditional elimination rule.