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: Surgery
A 20 year old male presents with chronic constipation, headache and palpitations. On examination he had marfanoid habitus, neuromas of tongue, medullated corneal nerve fibers and nodule of 2 x 2 cm size in It lobe of thyriod. This pt. is a case of - 
Select and explain. 
A. Sporadic medullary carcinoma of thyroid, B. Familial medullary carcinoma of thyroid, C. MEN IIA, D. MEN IIB
D: MEN IIB
Answer: D: MEN IIB 
Explanation: None