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: Radiology
Most radiosensitive tissue of body among the following is – 
Select and explain. 
A. Bone marrow, B. Spleen, C. Kidney, D. Brain
A: Bone marrow
Answer: A: Bone marrow 
Explanation: Bone & cartilage are radioresistant.
Ewing's sarcoma, seminoma and GI epithelium are highly radiosensitive.