A Researcher Is Interested in How Self-Esteem Varies Across the Lifespan

A researcher is interested in how self-esteem varies across the lifespan and decides to conduct a survey comparing people of different ages to address this issue. He recruits participants to be in one of four different age groups: 20 to 29, 30 to 39, 40 to 49, and 50 to 59. He has them complete a self-esteem survey, and then analyzes the data to see whether any patterns emerge. This study would be considered an example of a

A) longitudinal design
B) double-blind design
C) cross-sectional design
D) sequential design