Adelta is formed by deposition of sediment at the mouth of a river by water fanning out, and sand is an example of a clastic sediment. Given these facts, deltas are formed by deposition of what at the mouth of a river by water fanning out among the following options:
- air
 - water
 - salt
 - ice
 - soils
 - sand
 - rocks
 - barrel


 

      sand   