Correct Option: D. Oil refineries Explanation of the Correct Answer The point marked with solid triangles in the context of Nigeria's geography likely indicates the locations of oil refineries. Nigeria is one of the largest oil producers in Africa, and its economy heavily relies on the oil and gas sector. The country has several oil refineries that process crude oil into usable products such as gasoline, diesel, and other petrochemicals.

1. Understanding Oil Refineries:
2. Oil refineries are industrial facilities that convert crude oil into various petroleum products. They are strategically located near oil fields or transportation hubs to facilitate the processing and distribution of oil.
3. In Nigeria, major refineries include the Port Harcourt Refinery, the Warri Refinery, and the Kaduna Refinery. These facilities are crucial for meeting domestic fuel needs and for export.
4. Geographical Context:
5. The locations of these refineries are often marked on maps to highlight their importance in the energy sector. They are typically situated in regions with access to crude oil supplies and transportation infrastructure, such as pipelines and ports.
6. Economic Significance:
7. The oil industry is a significant contributor to Nigeria's GDP, and the refineries play a vital role in ensuring that the country can process its crude oil domestically rather than relying on imports for refined products.

Explanation of Why Other Options Are Incorrect

• A. Thermal power stations:
• While Nigeria does have thermal power stations that generate electricity, these facilities are not as concentrated or marked in the same way as oil refineries. Thermal power stations typically use natural gas or coal, and their locations are not as directly tied to the oil industry as refineries are.
• B. International airports:
• International airports are critical for transportation and trade, but they are not specifically related to the oil industry. Airports are spread across various regions of Nigeria and do not have a concentrated pattern like oil refineries. The solid triangles would not typically represent airport locations.
• C. Automobile assembly:
• Automobile assembly plants exist in Nigeria, but they are not as numerous or strategically located as oil refineries. The automobile industry is growing, but it does not dominate the geographical landscape in the same way that oil refineries do. The locations of assembly plants are more dispersed and not as critical to the national economy as oil refineries.

Summary of Key Points

• Nigeria's economy is heavily reliant on oil, making oil refineries crucial for processing crude oil.
• The solid triangles likely indicate the locations of major oil refineries, such as those in Port Harcourt, Warri, and Kaduna.
• Other options (thermal power stations, international airports, automobile assembly) do not have the same concentration or significance in relation to Nigeria's oil industry.
• Understanding the geographical distribution of these facilities is essential for grasping Nigeria's economic landscape.

This thorough understanding of the significance of oil refineries in Nigeria will help you in your geography studies and professional exams.