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: Physiology
[{'content': "Memory cells doesn't undergo apoptosis due to presence of which growth factor: \nSelect and explain. \nA. Platelet derived growth factor, B. Nerve growth factor, C. Insulin like growth factor, D. Fibroblast growth factor", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Nerve growth factor [Ref: Survival of memory B lymphocytes is tightly linked to the integrity of the Bel-2 protein and is regulated by a nerve growth factor (NGF) autocrine circuit. Nerve growth factor inhibits apoptosis in memory B lymphocytes inactivation of p38 MAPK, prevention of Bcl-2 phosphorylation, and cytrochrome c release. NGF is a classical survival factor, essential for a large number of cell types, including neurons, keratinocytes, and memory B lymphocytes.', 'role': 'assistant'}]