This is a question with answer options. Goal: how to keep sweet potatoes from turning dingy

Which of the following methods is more reasonable for accomplishing this goal?

Choices:
* add a dash of black food coloring, immediately after cooking, to brighten the color.;
* Add a slice of lemon to peeled sweet potatoes while cooking;...I think the answer is
Add a slice of lemon to peeled sweet potatoes while cooking