This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lung Tumors, Subject name: Pathology
Which of the following histological type lung carcinoma has worst prognosis - 
Select and explain. 
A. Squamous cell CA, B. Adenocarcinoma, C. Alveolar-carcinoma, D. Small cell carcinoma
D: Small cell carcinoma
Answer: D: Small cell carcinoma 
Explanation: Ans. is 'd' i.e., Small cell CA o Small cell carcinomas are the most aggresive of lung tumors, metastatize widely and are virually incurable by surgical means.