This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: AIIMS 2017, Subject name: Pathology
Which of the following anticoagulant preservative can be used to store blood, so that it can be kept for 35 days? 
Select and explain. 
A. Acid citrate dextrose (ACD), B. CPD Citrate phosphate dextrose, C. Citrate phosphate dextrose-adenine (CPD-A), D. CP2D - citrate phosphate double dextrose
C: Citrate phosphate dextrose-adenine (CPD-A)
Answer: C: Citrate phosphate dextrose-adenine (CPD-A) 
Explanation: Shelf life of the blood after adding above chemicals:- Acid citrate dextrose -> 21 days Citrate phosphate Dextrose -> 21 days Citrate phosphate Dextrose Adenine -> 35 days Saline Adenine Glucose Mannitol -> 42 days.