This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anatomy
[{'content': 'Evaluation of an infant reveals hypocalcemia due to a lack of parathyroid hormone. On x-ray, the thymic shadow is absent. Which of the following embryonic structures is involved \nSelect and explain. \nA. Third pharyngeal cleft, B. Fouh pharyngeal cleft, C. Third pharyngeal pouch, D. Fouh pharyngeal pouch', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Since thymus is missing, appropriate answer would be third pharyngeal pouch. This patient has got DiGeorge syndrome. DiGeorge syndrome causes migration defects of neural crest-derived tissues, paicularly affecting development of the third and fouh Branchial pouch (pharyngeal pouches)', 'role': 'assistant'}]