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: Pathology
ACTH producing lung carcinoma 
Select and explain. 
A. Small cell CA, B. Squamous cell CA, C. Mesothelioma, D. Bronchoadenocarcinoma
A: Small cell CA
Answer: A: Small cell CA 
Explanation: Ans. is 'a' i.e., Small cell carcinoma