Answer:
A. 2 times a day, morning and night
Explanation:
If you search up the question alone then it would say its's okay to stretch everyday, as long as you aren't overdoing it. Most people don't work out every day and only a few times a week, once a month wouldn't make any sense considering trying to stay healthy anf fit, and once a week wouldn't work either, considering that the question is asking how often. So the only logical answer here would be A.