Consider the following premises. Jessica is curious if and only if Charles is climbing a mountain. For all x, x will make tea. Jessica is not curious. Can we infer the following from them? If we can, name the inference rule being used: Charles is climbing a mountain.
 From the fact that for all x, x will make tea we can infer that Sarah is making tea via universal instantiation. Finally, from the fact that Jessica is curious if and only if Charles is climbing a mountain, and that Jessica is not curious we can infer that Charles is not climbing a mountain via biconditional elimination, which contradicts that Charles is climbing a mountain. Therefore, the answer is no.