Which of the Following Is a Major Argument AGAINST the Use

Which of the following is a major argument AGAINST the use of cross-sectional research designs in studying adult development?

A) They require too much time to collect data.
B) They typically involve non-representative samples.
C) They confound age and cohort.
D) They do not allow comparisons of sub-groups, such as middle-class and working-class, or black and white.