This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Apoptosis, Subject name: Pathology
[{'content': 'Apoptosis is initiated by? \nSelect and explain. \nA. Caspases, B. Bd-2, C. Bd-X, D. P53', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ANSWER: (A) CaspasesREF: Robbins 8th Edn Page 295-296See Mechanism of Apoptosis in Pathology 2013 Session 1', 'role': 'assistant'}]