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: Medicine
[{'content': "True abut 'X' Chromosome inactivation: \nSelect and explain. \nA. X gene, B. RNA interference, C. Seen in Male, D. All", 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. X-gene Although females have 2X chromosomes (XX), but due to inactivation (lyonization) genes on one X chromosome becomes transcriptionally inactive. Thus X inactivation prevents expression of most genes on one of the X- chromosome in every cell of femaleQ.', 'role': 'assistant'}]