Consider the following premises. If Jennifer works, then it is overcast. If Susan climbs a mountain, then Jennifer is working. Sarah is an artist if and only if Jennifer is sad. Sarah is not an artist. It is not overcast. Can we infer the following from them? If we can, name the inference rule being used: Susan is climbing a mountain.
 From the fact that if Jennifer works, then it is overcast, and that it is not overcast we can infer that Jennifer is not working via modus tollens. Finally, from the fact that if Susan climbs a mountain, then Jennifer is working, and that Jennifer is not working we can infer that Susan is not climbing a mountain via modus tollens, which contradicts that Susan is climbing a mountain. Therefore, the answer is no.