This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'Apoptosis is \nSelect and explain. \nA. Cell death induced by regulated intracellular program, B. Cell survival by a regulated ultra cellular program, C. Modification and adaptation by the regulated intracellular program, D. Cell death by an extracellular signal', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Apoptosis is a pathway of cell death in which cells activate enzymes that degrade the cells\' own nuclear DNA and nuclear and cytoplasmic proteins. Fragments of the apoptotic cells then break off, giving the appearance that is responsible for the name (apoptosis, "falling off").Apoptosis results from the activation of enzymes called caspases (so named because they are cysteine proteases that cleave proteins after aspaic residues)( Robbins Basic Pathology, 9th edition, page 19 )', 'role': 'assistant'}]