Correct Option: A. Lokoja-Ajaokuta Detailed Explanation: To determine which zone is the least industrialized in Nigeria among the given options, we need to analyze the industrial development and economic activities in each of these regions.

1. Lokoja-Ajaokuta:
2. Overview: Lokoja is the capital of Kogi State, and Ajaokuta is known for the Ajaokuta Steel Company, which was established to promote steel production in Nigeria. However, despite the presence of this steel company, the region has not fully developed into a robust industrial hub.
3. Industrial Activity: The industrial activities in this area are limited. The Ajaokuta Steel Company has faced numerous challenges, including mismanagement and lack of funding, which have hindered its operational capacity. Consequently, the overall industrial output in this zone remains low.
4. Conclusion: Due to these factors, Lokoja-Ajaokuta is considered the least industrialized zone among the options provided.
5. Lagos-Ikeja:
6. Overview: Lagos is Nigeria's largest city and a major economic hub. Ikeja, the capital of Lagos State, is home to numerous industries, including manufacturing, telecommunications, and finance.
7. Industrial Activity: The region boasts a high concentration of industries and is a center for commerce and trade. The presence of the Murtala Muhammed International Airport and several industrial estates further enhances its industrial profile.
8. Conclusion: This zone is highly industrialized compared to Lokoja-Ajaokuta.
9. Port Harcourt-Aba:
10. Overview: Port Harcourt is the capital of Rivers State and is known as the oil capital of Nigeria. Aba is famous for its manufacturing and trade, particularly in textiles and footwear.
11. Industrial Activity: The region has a strong industrial base, particularly in oil and gas, as well as manufacturing. Port Harcourt has numerous refineries and petrochemical industries, while Aba is known for its vibrant market and production of goods.
12. Conclusion: This zone is also highly industrialized, making it more developed than Lokoja-Ajaokuta.
13. Kaduna-Zaria:
14. Overview: Kaduna is a significant city in northern Nigeria, and Zaria is known for its educational institutions and agricultural activities.
15. Industrial Activity: The region has a mix of industries, including textiles, food processing, and manufacturing. Kaduna has historically been an industrial center, with several factories and production facilities.
16. Conclusion: While it may not be as industrialized as Lagos or Port Harcourt, it is still more developed than Lokoja-Ajaokuta.

Why Other Options Are Incorrect or Weaker:

• B. Lagos-Ikeja: This option is incorrect because it is one of the most industrialized regions in Nigeria, with a diverse range of industries and significant economic activity.
• C. Port Harcourt-Aba: This option is also incorrect as it is a major industrial zone, particularly due to its oil and gas industries, making it far more industrialized than Lokoja-Ajaokuta.
• D. Kaduna-Zaria: While not as industrialized as Lagos or Port Harcourt, Kaduna-Zaria still has a considerable industrial base and is more developed than Lokoja-Ajaokuta.

Summary for Revision:

• Lokoja-Ajaokuta is the least industrialized zone in Nigeria due to limited industrial activities and challenges faced by the Ajaokuta Steel Company.
• Lagos-Ikeja is highly industrialized, serving as Nigeria's economic hub.
• Port Harcourt-Aba is a major industrial zone, especially in oil and manufacturing.
• Kaduna-Zaria has a mix of industries but is still more developed than Lokoja-Ajaokuta.