ANSWER:
The correct option is C- African kingdoms became vulnerable to foreign influence ad invasion. African kingdoms were always trading kingdoms and traded in many commodities.
Step-by-step explanation:
The African kingdoms relied heavily on trade of various commodities like gold, salt and spices to prosper and gain wealth.
However, this reliance on trade made the African kingdoms vulnerable to foreign influences and invasions.
When the outer world came to know of the goods African kingdoms traded in, they wanted to trade with these kingdoms and even wanted to invade these for their wealth.