Which of the Following Scenarios Best Represents a Cross-Sectional Research

Which of the following scenarios best represents a cross-sectional research design?

A) A study examines individual political views across a life span. The researcher's hypothesis is that as individuals age, they become more conservative. The researcher randomly selects a sample from various age cohorts, to examine their political views on capital punishment, immigration, and federal spending.
B) A study examines individual political views across a life span. The researcher's hypothesis is that as individual's age, they become more conservative. The researcher randomly selects a sample from selected high school population and follows them for 50 years.
C) A study examines the relationship of individual political views and the amount of education they have completed. The researcher's hypothesis is that there is a positive relationship between education and liberal political views.
D) A study examines how individual political views change between 1981-1991 and 2001-2011.