This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2018, Subject name: Medicine
A 14 year old boy with difficulty in walking and behavioural disturbance, recovered from prolonged jaundice recently, has bluish pigmentation over lunula. The next investigation to be done: 
Select and explain. 
A. Nail fold cappillaroscopy, B. Slit lamp examination, C. Biopsy of the pigmented area, D. Ankle-brachial pressure index
B: Slit lamp examination
Answer: B: Slit lamp examination 
Explanation: Neurological involvement + Jaundice + Azure Nails (Bluish discoloration of nails) = Wilson's disease Dx: Slit lamp examination and 24 hrs urinary copper Rx: for Neurological feature - Tetrathiomolybdate