Select one answer. a gallup survey of 2322 adults (at least 18 years old) in the u. s. found that 408 of them have donated blood in the past two years. construct a 90% confidence interval for the population proportion of adults in the u. s. who have donated blood in the past two years. round your answer to three decimal places. 10 points (0.163, 0.189) a. (0.160, 0.191) b. c. (0.156, 0.196) d. o (0.154, 0.198)