Consider the following premises. For all z_4, if z_4 takes a plane, then z_4 is climbing a mountain. For all z_4, z_4 will drive a car or z_4 will take a plane. For all z_4, z_4 will drive a car if and only if z_4 will climb a mountain. There is at least one z_4 for which if z_4 were a police officer, then z_4 is not climbing a mountain. Can we infer the following from them? For all z_4, z_4 is a police officer.
 From the fact that for all z_4, z_4 will drive a car if and only if z_4 will climb a mountain we can infer that for all z_4, if z_4 drives a car, then z_4 is climbing a mountain. From the fact that for all z_4, if z_4 drives a car, then z_4 is climbing a mountain, that for all z_4, if z_4 takes a plane, then z_4 is climbing a mountain, and that for all z_4, z_4 will drive a car or z_4 will take a plane we can infer that for all z_4, z_4 will climb a mountain. Finally, from the fact that there is at least one z_4 for which if z_4 were a police officer, then z_4 is not climbing a mountain, and that for all z_4, z_4 will climb a mountain we can infer that there is at least one z_4 for which z_4 is not a police officer, which contradicts that For all z_4, z_4 is a police officer. Therefore, the answer is no.