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': 'Sudden death, right sided hea failure (cor pulmonale or cardiovascular collapse occur when ? \nSelect and explain. \nA. Small pulmonary embolism, B. Massive pulmonary embolism, C. 60% or more of pulmonary aery is obstructed with emboli, D. End aery obliteration', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., 60% or more of pulmonary aery is obstructed with emboli", 'role': 'assistant'}]