This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
In STD cases, a patient is asked to name other persons is his socio sexual group, then they are investigated. This is a example of - 
Select and explain. 
A. Screening, B. Contact tracing, C. Mass screening, D. High risk screening
B: Contact tracing
Answer: B: Contact tracing 
Explanation: <p> In Contact tracing the sexual paners of diagnosed patients are identified, located,investigated and treated. Patients are interviewed for their sexual contacts by specially trained staff. Reference:Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:339. <\p>