Consider the following premises. For all x_8, if x_8 drinks water, then x_8 is not sleeping. For all x_8, x_8 will drive a car if and only if x_8 will drink water. For all x_8, if x_8 drinks water, then x_8 is driving a car. For all x_8, x_8 will sleep. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_8 for which x_8 will drive a car.
 From the fact that for all x_8, x_8 will drive a car if and only if x_8 will drink water we can infer that for all x_8, if x_8 drives a car, then x_8 is drinking water via universal biconditional elimination. From the fact that for all x_8, if x_8 drinks water, then x_8 is driving a car, and that for all x_8, if x_8 drives a car, then x_8 is drinking water we can infer that for all x_8, x_8 will drink water if and only if x_8 will drive a car via universal biconditional introduction. From the fact that for all x_8, if x_8 drinks water, then x_8 is not sleeping, and that for all x_8, x_8 will sleep we can infer that for all x_8, x_8 will not drink water via universal modus tollens. Finally, from the fact that for all x_8, x_8 will drink water if and only if x_8 will drive a car, and that for all x_8, x_8 will not drink water we can infer that for all x_8, x_8 will not drive a car via universal biconditional elimination, which contradicts that There is at least one x_8 for which x_8 will drive a car. Therefore, the answer is no.