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 David drives a car, then it is sunny. If it is sunny, then Mary is drinking water. Mary is drinking water if and only if David is driving a car.
If David drives a car, then Mary is drinking water can be inferred via the transitivity rule. If Mary drinks water, then David is driving a car can be inferred via the biconditional elimination rule. If David drives a car, then Mary is drinking water can be inferred via the biconditional elimination rule.