Correct Option: C. Cola nitida and Cola acuminata Explanation of the Correct Answer Cola nitida and Cola acuminata are the two primary species of kola that are cultivated for commercial purposes in West Africa. These species are significant due to their economic value, particularly in the production of kola nuts, which are used in various beverages, traditional medicine, and cultural practices.

1. Cola nitida: This species is commonly known as the "bitter kola." It is highly valued for its seeds, which contain caffeine and theobromine, making them popular in traditional medicine and as a stimulant. The nuts are often chewed for their stimulating effects and are also used in the production of soft drinks.
2. Cola acuminata: Known as the "sweet kola," this species is also important for its seeds, which are sweeter than those of Cola nitida. It is often used in the same contexts as Cola nitida but is particularly favored for its taste. The seeds are also rich in caffeine and are used in various traditional practices.

Both species thrive in the humid tropical climates of West Africa, making them well-suited for cultivation in this region. Why the Other Options Are Incorrect

• Option A: Cola acuminata and Cola gigantea
• Cola gigantea is not a commonly cultivated species for commercial purposes. While it exists, it does not have the same economic significance as Cola nitida and Cola acuminata. Therefore, this option is incorrect.
• Option B: Cola nitida and Cola verticillata
• Cola verticillata is not widely recognized or cultivated for commercial purposes in West Africa. While it may exist, it does not hold the same importance as the other two species. Thus, this option is also incorrect.
• Option D: Cola verticillata and Cola gigantea
• Similar to the previous options, both Cola verticillata and Cola gigantea are not significant in commercial cultivation. They do not have the same level of economic impact or usage as Cola nitida and Cola acuminata. Therefore, this option is incorrect as well.

Summary of Key Points

• The two main species of kola grown for commercial purposes in West Africa are Cola nitida and Cola acuminata.
• Cola nitida is known for its bitter taste and stimulant properties, while Cola acuminata is sweeter and also valued for its caffeine content.
• Other options listed (Cola gigantea and Cola verticillata) do not have the same commercial significance in the region.
• Understanding the economic importance of these species is crucial for agricultural science and commercial cultivation practices in West Africa.

This detailed understanding of the kola species will help in recognizing their roles in agriculture and commerce, especially in the context of West African economies.