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: Medicine
A 25 year old male presented with pigmentation of nose and pinna. After voiding, his urine becomes dark. His spine is most likely to show - 
Select and explain. 
A. Atlantoaxial subluxation, B. Spondyloptosis, C. Basilar invagination, D. Calcification of disc
D: Calcification of disc
Answer: D: Calcification of disc 
Explanation: None