This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vermiform Appendix, Subject name: Surgery
[{'content': 'Which muscle is irritated by inflamed retrocaecal appendix - \nSelect and explain. \nA. Psoas major, B. Gluteus maximus, C. Quadratus femoris, D. Obturator internus', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Psoas major Abdominal pain in appendicitis:* In children with abdominal pain, who hold their right hip in a flexed position to obtain relief from the pain, one should suspect retrocaecal appendicitis causing irritation of the psoas muscle.", 'role': 'assistant'}]