Correct Option: A. Gongola Detailed Explanation: To determine which river is marked as "R," we need to analyze the geographical context and characteristics of the rivers listed in the options. The rivers mentioned are Gongola, Yobe, Gurara, and Taraba, all of which are located in Nigeria.

1. Understanding the Rivers:
2. Gongola River: This river is a major tributary of the Benue River and flows through the northeastern part of Nigeria. It is known for its significant role in the region's agriculture and irrigation.
3. Yobe River: This river is also a tributary of the Chad Basin and flows through the northeastern region of Nigeria, but it is less significant in terms of size compared to the Gongola.
4. Gurara River: This river is located in central Nigeria and is known for the Gurara Falls. It is a tributary of the Niger River.
5. Taraba River: This river is a tributary of the Benue River, flowing through the Taraba State in Nigeria.
6. Geographical Context:
7. The Gongola River is particularly notable for its size and the area it covers. It is essential to identify the geographical features associated with each river to ascertain which one is marked as "R."
8. If the question provides a map or specific geographical features (like tributaries, lakes, or cities), we can pinpoint the location of the Gongola River more accurately.
9. Why Gongola is Correct:
10. The Gongola River is the largest among the options provided and has a more extensive drainage basin. It is also more commonly referenced in geographical studies and maps of Nigeria.
11. If the question is based on a map, the Gongola River would likely be the most prominent river marked "R" due to its significant size and flow.

Why Other Options are Incorrect:

• B. Yobe: While the Yobe River is significant, it is not as large or prominent as the Gongola. It also has a different drainage pattern and is less frequently referenced in geographical contexts compared to the Gongola.
• C. Gurara: The Gurara River, while important, is primarily known for its falls and is smaller in size compared to the Gongola. It does not have the same level of recognition in terms of being a major river in Nigeria.
• D. Taraba: The Taraba River is also a tributary of the Benue but is less significant than the Gongola. It is not as widely recognized in geographical studies, making it a weaker option.

Summary of Key Points:

• The Gongola River is the largest and most significant river among the options provided.
• It plays a crucial role in the northeastern region of Nigeria, particularly in agriculture and irrigation.
• The other rivers (Yobe, Gurara, Taraba) are smaller and less prominent in geographical studies.
• Understanding the geographical context and characteristics of each river is essential for identifying them correctly.

Revision Summary:

• Gongola River is the largest and most significant river in the options.
• Yobe, Gurara, and Taraba are smaller and less prominent.
• Geographical context is crucial for identifying rivers correctly.
• Map analysis can help in determining the correct river based on size and drainage patterns.