This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and PNS, Subject name: ENT
[{'content': "Lymphoid tissue called Waldeyer's ring is situated in: \nSelect and explain. \nA. Nasopharynx, B. Oropharynx, C. Both nasopharynx and oropharynx, D. Base of tongue", 'role': 'user'}, {'content': "Answer: C \nExplanation: Waldeyer's ring consists of subepilhelial collection of lymphoid tissue. It comprises adenoid, tubal tonsil (both in nasopharynx) and palatine tonsils, lingual tonsils and granules in posterior pharyngeal wall (in oropharynx).", 'role': 'assistant'}]