Answer:
c at least 20 seconds
Explanation:
keeping your hands clean is very important ans washing them for 5 seconds doesn't do much, all the germs are still on them. washing you hands for a minute or even 5 minutes gets all the germs off but is a bit to long. So that's why 20 seconds is the perfect time and it gets most of the germs off. If you need a timer just sing the happy birthday song twice out loud or in you head.
