Concept:The main cause of the Benin Kingdom's decline in the 19th century was European colonial expansion in Africa.
Explanation:The Scramble for Africa was the late 19th-century rush by European powers to colonize African territories.
This event brought British military pressure and political interference into the Benin Kingdom.
In 1897, a British punitive expedition sacked Benin City, which weakened the kingdom's monarch and its influence.
The American Civil War, the Opium Wars, and the French Revolution were distant events that did not directly affect Benin.
Answer:B. The Scramble for Africa