Among the options given on the question the correct answer is option C.
African slaves.
Explanation: When the American and the Native Indian had a series of devastating war the working sector was hampered greatly.After the end of war a lot of native working population died due to the war.As a result there was a shortage of workers in the market.
At this time to end up this crisis the Americans started to bring African slaves in america to replace the died off workers.The trans Atlantic slave trade was a key event on the slave trade of the America. Moreover, the African slaves were more easy bring and make them hard.
As a result the slave business from Africa to America new slavery era.
The answer is B because the Mechanical Reaper changed the way the world worked at the time; It made the demand for slaves go up as the work necessitated some manual work
