Which of the following problem has the least effect on agricultural productivity in West Africa?

Of the options listed, illiteracy is likely to have the least effect on agricultural productivity in West Africa. Illiteracy refers to the inability to read or write, and while it can be a barrier to accessing information and education, it is not directly related to agricultural productivity. Farmers can still have knowledge of traditional farming methods and local environmental conditions without being able to read or write. In addition, there are many extension services and NGOs working to provide education and training to farmers in West Africa, which can help to overcome the challenges posed by illiteracy. On the other hand, the incidence of pests and diseases, unfavorable weather conditions, and urban-rural migration are all major challenges that can significantly impact agricultural productivity in West Africa. Pests and diseases can destroy crops and reduce yields, unfavorable weather conditions such as droughts and floods can damage crops and cause food shortages, and urban-rural migration can reduce the labor force available for farming and lead to the abandonment of farmland. Therefore, while illiteracy remains a significant issue in West Africa, it is likely to have the least effect on agricultural productivity compared to the other options listed.