Probably what is the 20 20 20 rule
A.Every twenty minutes, look away twenty feet or more for at least twenty seconds from whatever device you’re using.
B.Every twenty feet, look away twenty minutes or more for at least twenty seconds from whatever device you’re using.
C.Every twenty feet, look away twenty seconds or more for at least twenty feet from whatever device you’re using.
D.Every twenty seconds, look away twenty feet or more for at least twenty minutes from whatever device you’re usin