B. cultural diffusion most contributed to the development of trade among the different people of Africa because Cultural diffusion refers to the spread of cultural elements such as language, ideas, and customs from one group of people to another. In the case of Africa, cultural diffusion allowed different groups of people to exchange goods, ideas, and technologies, which facilitated the development of trade. For example, the spread of ironworking technology and the use of camels as pack animals helped to increase the volume and efficiency of trade across the Sahara. Similarly, the spread of the Swahili language and culture along the East African coast facilitated trade between African societies and the Arab world. Cultural diffusion also helped to create networks of trade that linked different regions of Africa together, such as the trans-Saharan trade routes or the Indian Ocean trade network.