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 snows, then Karen is an astronaut. Karen is an astronaut if and only if it is cloudy. It is overcast. It is not cloudy.
It is overcast and it is not cloudy can be inferred via the conjunction rule. It is not cloudy and it is overcast can be inferred via the conjunction rule. If Karen were an astronaut, then it is cloudy can be inferred via the biconditional elimination rule. If it is cloudy, then Karen is an astronaut can be inferred via the biconditional elimination rule. Karen is not an astronaut can be inferred via the biconditional elimination rule.