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
Role of fixer is: 
Select and explain. 
A. It binds developer to film, B. It takes away extra developer solution, C. It strengthens/fixes the silver halides on to X-ray film, D. It removes the extra silver halides which are unfixed
D: It removes the extra silver halides which are unfixed
Answer: D: It removes the extra silver halides which are unfixed 
Explanation: None