Consider the following premises. For all x_9, if x_9 were a police officer, then x_9 is an office clerk. For all x_9, x_9 will not drive a car. For all x_9, x_9 is an office clerk if and only if x_9 will drive a car. For all x_9, if x_9 were an office clerk, then x_9 is a police officer. Can we infer the following from them? For all x_9, x_9 is not a police officer.
 From the fact that for all x_9, if x_9 were a police officer, then x_9 is an office clerk, and that for all x_9, if x_9 were an office clerk, then x_9 is a police officer we can infer that for all x_9, x_9 is a police officer if and only if x_9 is an office clerk. From the fact that for all x_9, x_9 is an office clerk if and only if x_9 will drive a car, and that for all x_9, x_9 will not drive a car we can infer that for all x_9, x_9 is not an office clerk. From the fact that for all x_9, x_9 is a police officer if and only if x_9 is an office clerk we can infer that for all x_9, if x_9 were a police officer, then x_9 is an office clerk. Finally, from the fact that for all x_9, if x_9 were a police officer, then x_9 is an office clerk, and that for all x_9, x_9 is not an office clerk we can infer that for all x_9, x_9 is not a police officer. Therefore, the answer is yes.