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: Mary is not a carpenter or it is overcast. For all x_11, x_11 is a carpenter or x_11 is an astronaut. It is cold if and only if Barbara is drinking water. If Mary were an astronaut, then it is cold. Barbara is not drinking water.
If it is cold, then Barbara is drinking water can be inferred via the biconditional elimination rule. If Barbara drinks water, then it is cold can be inferred via the biconditional elimination rule. It is not cold can be inferred via the biconditional elimination rule.