<span>The correct answer should be A. The work required on plantations could only be done by slaves. The slaves were even cheaper than indentured servants and could be controlled more easily. They could just import them and keep them forever while indentured servants often caused problems like the famous Bacon's rebellion.</span>
The first cause of the decline of Byzantine Empire was the Arab wars. In the west side of Byzantium conflicts rose and began to cause trouble for the Empire.
Czechoslovakia was annexed by Germany 4 months before the beginning of ww2
The electoral college elects the president.
I hope this helps.