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 Richard were a musician, then David is climbing a mountain. Mary is poor if and only if Richard is a musician. It is not windy. David is climbing a mountain if and only if it is windy.
If Mary were poor, then Richard is a musician can be inferred via the biconditional elimination rule. If David climbs a mountain, then it is windy can be inferred via the biconditional elimination rule. If Richard were a musician, then Mary is poor can be inferred via the biconditional elimination rule. If it is windy, then David is climbing a mountain can be inferred via the biconditional elimination rule. David is not climbing a mountain can be inferred via the biconditional elimination rule.