Atrade magazine routinely checks the drive-through service times of fast-food restaurants. upper aa 9090% confidence interval that results from examining 503503 customers in one fast-food chain's drive-through has a lower bound of 168.7168.7 seconds and an upper bound of 171.7171.7 seconds. what does this mean? choose the correct answer below. a. the mean drive-through service time of this fast-food chain is nothing seconds nothing% of the time. b. one can be nothing% confident that the mean drive-through service time of this fast-food chain is nothing seconds. c. there is a nothing% probability that the mean drive-through service time of this fast-food chain is between nothing seconds and nothing seconds. d. one can be 9090% confident that the mean drive-through service time of this fast-food chain is between 168.7168.7 seconds and 171.1171.1 seconds.