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
[{'content': 'Vitamin A activity is inhibited by \nSelect and explain. \nA. Linetin, B. Black berries, C. Citral, D. Red cabbage', 'role': 'user'}, {'content': 'Answer: C \nExplanation: These results suggest that\xa0citral inhibits\xa0both the natural\xa0vitamin\xa0A in the plasma and the added synthetic\xa0vitamin\xa0A, thus producing changes in the tracheal epithelium characteristic of\xa0vitamin\xa0A deficiency.\nRef :\xa0The Effects of Vitamin A and Citral on Epithelial Differentiation in vitro,\xa0J. Embryol. exp. Morph., Vol. 11, Part 1, pp. 279-291', 'role': 'assistant'}]