The fact that anyone can get it even if they can get something better
The problems are the overgrazing, salinization(<span>Soil salinity)</span> and water availability.
These are included to be the problems of agriculturists in the region
10 percent plan: A model for reinstatement of Southern states, offered by Abraham Lincoln in December 1863, that decreed that a state could be reintegrated into the Union when 10 percent of the 1860 vote count from that state had taken an oath of allegiance to the United States and pledged to abide by emancipation. The next step in the process would be for the states to formally elect a state government. Also, a state legislature could write a new constitution, but it also had to abolish slavery forever. At that time, Lincoln would recognize the reconstructed government.
The brown tree snake is actually really infamous for being an invasive species so C would be the answer.
