This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Integrated QBank, Subject name: Unknown
[{'content': 'A 65-year-old man with H/O 30 pack years of smoking presents with weight loss, cough with expectoration and hemoptysis for 40 days. Serum Na was found to be 124 mEq/L. Serum Ca -10 mg/dl. Chest X ray showed a hilar mass. Brush cytology and sputum was positive for tumor cells. What of the following subtypes of lung carcinoma does this this patient most likely have? \nSelect and explain. \nA. Squamous cell carcinoma, B. Adenocarcinoma, C. Small cell carcinoma, D. Large cell carcinoma', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Hilar mass suggests either squamous cell or small cell carcinoma. Hyponatremia due to SIADH is more likely in ors of Small cell. Hypercalcemia and cavitation are more likely in ors of squamous cell carcinoma', 'role': 'assistant'}]