Answer:
C. Grain
A. Gold
Explanation:
Egypt and Kush had close ties, and they had lot of trade going on between them. Lot of products were traded between these two civilizations, but the main focus was around the grain and gold. Egypt highly valued the gold, but it didn't had its own reserves of it. The Kush lacked food sources, such as grain. Because of this, Egypt provided Kush with grain that it had in abundance, while Kush provided Egypt with gold which it had abundance, so both sides benefited from it.
