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
Patientswith STD are asked to name other persons of either sex who move in the same socio sexual environment. These patients are then screened for the disease. This process is known as: 
Select and explain. 
A. Cluster testing, B. Mass screening, C. High risk screening, D. None of the above
A: Cluster testing
Answer: A: Cluster testing 
Explanation: Patients of STD are asked to name other persons of either sex who move in the same socio sexual environment. These patients are then screened for the disease. This process is known as cluster testing. This technique is shown to double the cases found. Ref: Park 21st edition, page 313.