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
Principle for chinese medicine - 
Select and explain. 
A. Yang, B. Vin, C. Both, D. None
C: Both
Answer: C: Both 
Explanation: Ans. is 'c' i.e., Both o Chinese medicine is based on two principles:- i) Yang : Active masculine principle ii) Vin : Negative feminine principle o The balance of these two opposing forces meant good health. o The Chinese were early pioneers of immunization. They practised variolation to prevent smallpox. o The Chinese system of 'bare-foot doctors' and accupuncture have attracted worldwide attention in recent years.