Which region specializes in diamonds?

The correct answer is D. Sub-Saharan Africa.

Sub-Saharan Africa is known for being rich in diamond resources, with countries like Botswana, South Africa, and the Democratic Republic of the Congo being significant producers of diamonds. This region has some of the largest diamond mines in the world, making it a key player in the global diamond industry. If you have more questions or need further assistance, feel free to ask!