Answer:
C. to start cotton plantation
Explanation:
People moved to the west in the mid-1800s due to the "Homestead Act" that was signed by President Abraham Lincoln. This act distributed the wild lands to people thus, giving them the opportunity to have a free land which they could cultivate. This makes letter A (to obtain free land) as one reason.
It was, supposedly, an opportunity for different individuals such as farmers, cowboys and miners. Many people were driven to the west in search for gold, silver and copper. This makes letters B (to establish cattle ranches) and D (to prospect for gold) as other reasons.
However, it became harder for American farmers to grow crops. Plantation was mainly focused on wheat and corn. So, this makes letter C (to start cotton plantation) as incorrect.
