Fact 1: Adelta is formed by deposition of sediment at the mouth of a river by water fanning out.

Fact 2: Sand is an example of a clastic sediment.

Given the two facts above, answer the question "Deltas are formed by deposition of what at the mouth of a river by water fanning out?" with the following options: 
- air
 - water
 - salt
 - ice
 - soils
 - sand
 - rocks
 - barrel


 

      sand   