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
Surveillance is: March 2005 
Select and explain. 
A. Monitoring of activity of health workers, B. Continuous monitoring of occurrence and distribution of a disease, C. Monitoring of trends of a disease, D. Related to the virulence of the organism
B: Continuous monitoring of occurrence and distribution of a disease
Answer: B: Continuous monitoring of occurrence and distribution of a disease 
Explanation: Ans. B: Continuous monitoring of occurrence and distribution of a disease