In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.
Q: Menthol cigarettes are constructed similarly to non-mentholated cigarettes, with menthol added at any of several stages during the manufacturing process. Menthol may be derived from distilled corn mint oil, or produced synthetically. While trace amounts of menthol may be added to non-mentholated cigarettes for flavor or other reasons, a menthol cigarette typically has at least 0.3% menthol content by weight. Lower-tar menthol cigarettes may have menthol levels up to 2%, in order to keep menthol delivery constant despite the filtration and ventilation designs used to reduce tar.
A:
where does the menthol in cigarettes come from