This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Introduction, Subject name: Pathology
[{'content': 'In-situ DNA nick end labeling can quantitate: \nSelect and explain. \nA. Fraction of cells in apoptotic pathways, B. Fraction of cells in S phase, C. p53 gene product, D. bcr/abl gene', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In situ DNA nick end - labeling In-situ method for detecting areas of DNA which are nicked during apoptosis. Terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL) is a method for detecting apoptotic cells that exhibit DNA fragmentation.', 'role': 'assistant'}]