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: Biochemistry
Which of the following combinations of biologically active molecules does vitamin A consists of 
Select and explain. 
A. Retinol, retinal and retinoic acid, B. Retinol, retinal and tetrahydrofolate, C. Retinal, conjugase and retinoic acid, D. PABA, retinal and retinaldehyde
A: Retinol, retinal and retinoic acid
Answer: A: Retinol, retinal and retinoic acid 
Explanation: A i.e. Retinol, Retinal, and Retinoic acid