The oxidation of retinol produces:-: (A) Retinine, (B) Beta-carotene, (C) Retinal, (D) Retinoic acid
Answer is C. Retinal (vitamin A aldehyde): 
This is an aldehyde form obtained by the oxidation of retinol. 
Retinal and retinol are interconvertible.
Key Concept:
Oxidation of retinol produces retinal
Oxidation of retinal produces retinoic acid.
Ref : Textbook of Biochemistry, Satyanarayana