This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
[{'content': 'How long can blood be stored with CPD-A - \nSelect and explain. \nA. 21 days, B. 28 days, C. 35 days, D. 42 days', 'role': 'user'}, {'content': 'Answer: C \nExplanation: blood can be stored only 21 days with CPD Where as when adenine is added to CPD , it can be stored for 35 days citrate phosphate dextrose adenine (CPDA-1) an anticoagulant solution, containing citric acid, sodium citrate, monobasic sodium phosphate, dextrose, and adenine, used for the preservation of whole blood and red blood cells for up to 35 days; it extends red cell survival by providing adenine needed for the maintenance Refer robbins 9/e pg 450', 'role': 'assistant'}]