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: Ophthalmology
Transport of Ascorbic acid to the lens is done by – 
Select and explain. 
A. Myoinositol, B. Choline, C. Taurine, D. Na– K ATP ase
D: Na– K ATP ase
Answer: D: Na– K ATP ase 
Explanation: I could not find any direct reference for this. I could find only following information.
Ascorbic acid is not synthesized in the lens, but there is evidence that specialized transport mechanism exist to transport it into the lens. Ascorbic acid is transported into the lens by Na+ dependent specific transporter, i.e. specific vitamin C transporter (SVCT) SVCT1 & SVCT2.
So, amongst the given options Na+ K+ ATPase seems to be best as ascorbic acid transport is Na+ dependent. But, I am not 100% sure.