This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Arthritis, Subject name: Orthopaedics
[{'content': 'Which of the following crystals found in Pseudo gout: \nSelect and explain. \nA. Monosodium urate mohohydrate, B. Calcium pyrophosphate dihydrate, C. Calcium hydroxyapatite, D. Alkaline phosphatase', 'role': 'user'}, {'content': 'Answer: B \nExplanation: (Calcium pyrophosphate dihydrate): Ref: 69- 73-ACRYSTALDISEASE1. Monosodium urate- Gout2. Calcium pyrophosphate dihydrate- Chondrocalcinosis- Pseudogout- Chronic pyrophosphate arthropathy3. Calcium hydroxyapatitie- Acute or subacute periarthritis- Chronic destructive arthritisGout: - Smaller joint (metacarpophalangeal joint of the big toes commonest site) pain intense, joint inflamed: Hyperuricemia, urate crystals are needle like 5-20 cm, long, and exhibit strong negative birefringencePSEUDO-GOUT: - Large joint, pain moderate, joint swollen, chondrocalcinosis, Pyrophosphate crystals are rhomboid-shaped, slightly smaller than urate crystals and show weak positive birefringence', 'role': 'assistant'}]