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: Forensic Medicine
For diatoms test the best site for taking sample is 
Select and explain. 
A. Lungs, B. Bone marrow in Ulna, C. Bone marrow in femur, D. Muscle
C: Bone marrow in femur
Answer: C: Bone marrow in femur 
Explanation: C i.e. Bone marrow in femur