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: It is snowing or Barbara is running. It is not snowing or Robert is driving a car. Robert is driving a car if and only if Barbara is a poet. For all x_13, if x_13 goes running, then x_13 is a poet.
Barbara is running or Robert is driving a car can be inferred via the resolution rule. If Barbara were a police officer, then it is snowing can be inferred via the rewriting rule. If Robert drives a car, then Barbara is a poet can be inferred via the biconditional elimination rule. If Barbara were a poet, then Robert is driving a car can be inferred via the biconditional elimination rule.