You are presented with the question "Rivers are usually larger than what" and the following answer choices: 
- objects that have mass
 - body water
 - colder and wetter
 - Veins and arteries.
 - allow growth
 - loose soil
 - at or near the margins
 - mountain sources

Now knowing that rivers are usually larger than streams and mountain stream water is drinkable, choose the best answer.


 

        mountain sources 