Vitamins and Coenzymes
The vitamin riboflavin, which occurs as a yellow pigment in egg yolk and milk become

colorless on oxidation and regained its color on reduction with Zn in acid
colorless on reduction with Zn in acid and regained its color on re-oxidation
more deep in color on oxidation and regained its color on reduction with Zn in acid
more deep in color on reduction with Zn in acid and regained its color on re-oxidation

ANSWER DOWNLOAD EXAMIANS APP