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
Commonly used Rodenticide is- 
Select and explain. 
A. Zinc sulphate, B. Copper sulphate, C. Zinc oxide, D. None
D: None
Answer: D: None 
Explanation: Ans. is 'None'