Which option completes the text below correctly? There are ____different op...

Which option completes the text below correctly?
There are ____different opinions on how ____ water you should be drinking every day. Health authorities commonly recommend eight 8- ounce glasses, which equals about 2 liters, or half a gallon. This is called the 8x8 rule and is very easy to remember. However, _____ health gurus believe that you need to sip on water constantly throughout the day, even when you're not thirsty. As with most things, this depends on the individual. _____ factors (both internal and external) ultimately affect your need for water.
(https://www.healthline.com)