It turned the water very deep indigo . When several more rinses failed to show a decrease in the amount of dye loss , I tried a vinegar rinse . That water came up clear , so assuming the problem was arrested , I got one more pan of cool water to rinse some of the vinegar smell from the shawl .

Generate a question about the above context.
Why was the narrator using vinegar ?
Available options: (I). To deal with the cooking . (II). None of the above choices . (III). To deal with issues with color in clothing . (IV). To make the food item more bitter .