This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Medicine
Following are risk factors for contrast nephropathy EXCEPT- 
Select and explain. 
A. Metformin, B. Dehydration, C. NSAIDs, D. Half normal saline
D: Half normal saline
Answer: D: Half normal saline 
Explanation: Risk factors for contrast nephropathy are- Older age CKD Hypoalbuminemia Pre renal Azotemia Dehydration Severe infection Diabetic nephropathy Patients on other nephrotoxic drugs PPI'S, NSAIDS, aminoglycosides, amphotericin B, cisplatin, carboplatin, Cyclosporine ,ARB'S /ACE-inhibitors Ref:Harrison 20 th edition pg no 2103,2099