Which of the following does not contribute to the high cost of building and maintaining roads in West Africa?

The option that does not contribute to the high cost of building and maintaining roads in West Africa is the infertility of some lands. Infertility means the land is unable to produce crops or plants, but this does not necessarily affect the construction and maintenance of roads. On the other hand, the swampy coastal areas, numerous rivers to be crossed, mountainous nature of some regions, and torrential downpour are all factors that contribute to the high cost of building and maintaining roads in West Africa. For instance, building roads in swampy coastal areas or regions with numerous rivers would require expensive bridge constructions or land reclamation, which would add to the overall cost. Similarly, constructing roads in mountainous regions would require more resources and effort due to the difficult terrain, while torrential downpour can easily damage roads, leading to higher maintenance costs.