This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
A 16 Yr old presented to the clinic with recurrent joint pains,dark spots in sclera,blackening of urine on standing.What is the most probable diagnosis? 
Select and explain. 
A. Alkaptonuria, B. Tyrosinemia, C. Phenylketonuria, D. All of the above
A: Alkaptonuria
Answer: A: Alkaptonuria 
Explanation: Reference: Harpers illustrated biochemistry 30th edition