The correct answer is D) Zimbabwe.
From the 500s to the 1500s, three African empires are primarily known for their trade across the Sahara Desert. The empire that would LEAST LIKELY fit in these parameters of a "Sudanic Kingdom" is Zimbabwe.
The Sahara Desert trade routes represented important trade connection routes to trade salt, gold, ivory, and slaves all through western Africa and up to northern Africa in places such as Djenne, Gao, Timbuktu, Agadez, Cairo, and Marrakesh.