This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
Vaccine which requires stringent condition for storage 
Select and explain. 
A. DPT, B. OPV, C. BCG, D. TT
B: OPV
Answer: B: OPV 
Explanation: (Refer: K. Park's Textbook of Preventive and Social medicine, 24th edition, pg no: 222)