Answer:
C
Explanation:
Why it isn't A: It isn't really poorly located. There are many opportunities regarding trading in Africa. Africa isn't a landlocked country like Afghanistan. For the most part, the reason Afghanistan is a poor country in the first place is that the country is landlocked. This does not allow for much trading to occur.
Why it isn't B: There is no evidence whatsoever saying that Africa has a small population. Africa has an extremely large population. In some cases, the large population creates a huge problem. (With this huge population, however, creates an alarmingly large amount of diseases that fall into the same category that HIV/AIDS do *you should know what I mean*)
The reason the answer is C: The tropical climate in Africa brings many diseases and animals that carry them, such as mosquitos. Malaria is also a huge problem in Africa, because there are so many mosquitos in the area. The tropical climates bring these pests, which then bite people.
Why it isn't D: Africa is extremely resource-rich. South Africa specializes in diamonds and Nigeria, oil. Many other African nations have their own special resources. This makes for huge trading opportunities.
Sorry for the lengthy response, but I hope this helps! :D
