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: John is making tea if and only if it is sunny. John is making tea or it is not sunny.
If it is sunny, then John is making tea can be inferred via the rewriting rule. If John makes tea, then it is sunny can be inferred via the biconditional elimination rule. If it is sunny, then John is making tea can be inferred via the biconditional elimination rule.