The Egyptian empire began to crumble in the 6th century B.C. when it was first attacked by the Babylonians. However, the Pharaohs were officially wiped out when the Persians killed Pharaoh Psamatik III.
Since this is a multiple choice question, I would choose C, Babylonians.
The answer is faults because when divergent boundaries occur, the tectonic plates move away from each other, therefor creating a fault in the earths crust.
I would go with D, because acid can be reduced by using it less
A balsalt I think is the answer I might be wrong sorry