A major cause of depopulation in Nigeria in the 18th century was

A.

The trans-Atlantic slave trade

B.

The trans-Saharan trade

C.

Human sacrifice

D.

Inter-ethnic warfare

Correct answer is A

The Trans-Saharan Trade which had been on for many centuries included several articles of trade of which slaves were later added; human sacrifice was only carried on a very small scale; interethnic warfare took place majorly in the
nineteenth century.