Every ten years the United States takes a census, which is a survey of every person in the country. If you took the census data that told you the number of people in the United States, and if from all of those numbers you calculated the mean age, what symbols would you use to represent these numeric facts? O A. nand x. O B. Nand i. O c. Nand x. O D. E and x. O E. nand y