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
Which of the following is the number of national helpline for HIV/AIDS? 
Select and explain. 
A. 1081, B. 1091, C. 1097, D. 1100
C: 1097
Answer: C: 1097 
Explanation: A toll free national AIDS telephone help line has been set up to provide access to information and counselling. Ref: Park 21st edition, page 399.