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 drinks water, then it is cloudy. If Karen were fast, then David is drinking water. It is cloudy if and only if William is bored. William is bored or Richard is working. Karen is fast or Richard is not working.
If Karen were fast, then it is cloudy can be inferred via the transitivity rule. If Richard works, then Karen is fast can be inferred via the rewriting rule. If it is cloudy, then William is bored can be inferred via the biconditional elimination rule. If William were bored, then it is cloudy can be inferred via the biconditional elimination rule.