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 it is sunny, then Robert is an electrician. William is not playing tennis. William is playing tennis if and only if Barbara is climbing a mountain. It is sunny.
Robert is an electrician can be inferred via the modus ponens rule. William is not playing tennis and it is sunny can be inferred via the conjunction rule. It is sunny and William is not playing tennis can be inferred via the conjunction rule. If William plays tennis, then Barbara is climbing a mountain can be inferred via the biconditional elimination rule. If Barbara climbs a mountain, then William is playing tennis can be inferred via the biconditional elimination rule. Barbara is not climbing a mountain can be inferred via the biconditional elimination rule.