This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
Which of the following stones is hard to break by ESWL 
Select and explain. 
A. Calcium oxalate monohydrate, B. Calcium oxalate dihydrate, C. Uric acid, D. Struvite
A: Calcium oxalate monohydrate
Answer: A: Calcium oxalate monohydrate 
Explanation: In general CYTINE , calcium phosphate,specifically Brushite ( Calcium phosphate Hydroxyapatite) and Calcium oxalate monohydrate stones , Matrix stones ( Protien rich stone) are most resistant to ESWL . All these are RADIO OPAQUE. Treatment of choice:- Renoscopic removal. The remainder of common stone type by order of increasing fragility are struvite , calcium oxalate dihydrate and finally uric acid stones.These are RADIO LUCENT ref :- Campbell - Walsh urology 11th edition .chapter 53 , pg no :- 1242 Bailey and Love 27th edition . chapter 76 , pg no 1408.