Which of the Following Is True of Using Census Data

Which of the following is true of using census data for in-depth demographic information?

A) All nations have census data and publish their census reports in English.
B) Data contained in a census are uniform across all countries.
C) Data contained in a census often omit items of interest to researchers.
D) Since a market researcher does not encounter problems in using census data, it is considered the best source of demographic information.