This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Intravascular heamolysis occurs in \nSelect and explain. \nA. Hereditory spherocytosis, B. Antoimmune haemolytic anemia, C. Paroxysmal nocturnal hemoglobinuria, D. Thalassemia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Paroxysmal noctural hemoglobunuria (PNH) is the only hemolytic anemia caused by an acquired intrinsic defect in the cell membrane. It is associated with intravascular hemolysis. Rest all conditions causes extravascular heamolysis.', 'role': 'assistant'}]