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: Microbiology
Not an enrichment medium ? 
Select and explain. 
A. Selenite F broth, B. Tetrathionate broth, C. Alkaline peptone water, D. Loeffler's serum
D: Loeffler's serum
Answer: D: Loeffler's serum 
Explanation: Ans. is `d' i.e., Loeffler's serum