A study is conducted to determine the extent to which drinking alcohol impairs driving ability. Forty volunteers are each tested twice on a computer simulated driving course, once while sober and once while intoxicated. The tests took place over two days and the order of the treatments were randomly assigned to each volunteer. One of the variables measured is the response time (in seconds) to a certain stimuli. The mean difference in response times measured while intoxicated versus sober is 0.914 seconds with standard deviation 1.496 seconds. Specify the correct number from the list below that corresponds to the appropriate null and alternative hypotheses for this problem.