The American Optometric Association Recommends Children Participate in Outdoor Activities

The American Optometric Association recommends children participate in outdoor activities using the 20-20-20 rule.What is the meaning of this rule?

A) Children should spend 20 minutes a day outside over a span of 20 days.
B) Children should spend 20 minutes a day talking to 20 friends over a span of 20 days.
C) For every 20 minutes spent outside, children should spend at least 20 minutes reading 20 pages from a book.
D) For every 20 minutes spent on a computer or reading, children should spend 20 seconds looking at things at least 20 feet away.