Concept:The leading industrial zone is the one with the greatest number, size, and diversity of manufacturing industries in West Africa.
Explanation:The Western industrial zone of Nigeria, centred on Lagos and its surroundings, is the most developed in the sub-region.
It holds the largest concentration of factories, including textile, food processing, chemical, and automobile assembly plants.
This zone benefits from advantages such as a huge consumer market, well-developed seaports, abundant skilled labour, and reliable electricity and transport networks.
The Accra-Tema zone in Ghana is significant but smaller in total industrial output and employment.
The Freetown and Banjul zones have limited industrial scale compared with the Nigerian Western zone.
Therefore, the Western industrial zone of Nigeria clearly leads the West African sub-region in industrial development.
Answer:A. Western industrial zone of Nigeria