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: Physiology
A 65-year-old chronic smoker presents with a rapidly enlarging large hilar mass on a chest film associated with significant adenopathy. He also experiences recurrent hypoglycemic spells these days. A provisional diagnosis of Lung carcinoma being considered which of the following subtype will most commonly lead to this spectrum? 
Select and explain. 
A. Squamous cell carcinoma, B. Adenocarcinoma, C. Large cell carcinoma, D. Small cell tumour
D: Small cell tumour
Answer: D: Small cell tumour 
Explanation: Small cell - Mediastinal adenopathy, - Hilar mass, - Small or invisibleftlung nodule, - High metastatic potential, - Rapid growth. - May be associated with Hypoglycemia, Cushing's syndrome, Inappropriate secretion of ADH, excessive gonadotropin secretion.