the land drained by a river and its tributaries the land formed when rivers create estuaries and marshes the land at the mouth of a river where water flows into the ocean the land formed as a result of a river flooding
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which best describes the characteristics of a river basin?
Possibilities:
- the land drained by a river and its tributaries
- the land formed when rivers create estuaries and marshes
- the land at the mouth of a river where water flows into the ocean
- the land formed as a result of a river flooding

the land drained by a river and its tributaries