Problem: An epidemiologist conducted a study to examine Diet X and chronic disease D. She surveyed 1,000 in her study and collected data on whether the participants had the disease and on their dietary history. Among the total respondents, the epidemiologist identified 250 people with the disease. One-hundred participants with chronic disease D reported that they had primarily followed diet X. What type of study is this? Group of answer choices Case-control study Ecological study Cross-sectional study Cohort study