This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pigmentation, Subject name: Pathology
[{'content': 'Which of the following is true about calcification? \nSelect and explain. \nA. It is most commonly seen in the kidneys, B. Serum calcium is normal in metastatic calcification, C. Psammoma body is formed with dystrophic calcification, D. Mitochondria is the rarest organelle affected in calcification', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Types of Calcification Feature DYSTROPHIC CALCIFICATION METASTATIC CALCIFICATION Definition Deposits of calcium salts in dead and degenerated tissues Deposits of calcium salts in normal tissues Cause Necrosis Infarcts Thrombi Haematomas Dead parasites Atheromas Ceain tumours Cysts Calcinosis cutis Old scars,etc Hyperparathyroidism Hyperplasia Bony destructive lesions Hypercalcaemia of infancy Prolonged immobilisation Hypervitaminosis D Milk-alkali syndrome Calcium metabolism Normal Deranged Serum Calcium Level Normal Hypercalcaemia', 'role': 'assistant'}]