Answer: D. Soybeans
Step-by-step explanation:
The diagram is not included but this should be the correct answer.
South American nations together produce the most amount of soybeans of any other areas in the world with them being responsible for almost 51% of world soybeans production.
Indeed of the 11 largest producers on the planet, there are 5 South American countries on that list with Brazil being the largest in the world and Argentina being third. Soybeans are therefore main natural resource in South America.