This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
A total of 5000 pts of glaucoma are identified and surveyed by pts. interviews regarding family history of glaucoma. Such a study design is called - 
Select and explain. 
A. Case series report, B. Case control study, C. Clinical trial, D. Cohort study
A: Case series report
Answer: A: Case series report 
Explanation: None