Egypt was motivated to conquer Nubia because of a desire for gold.
Option B
Explanation:
Nubia was a rich source of gold along with ebony, incense and ivory. Nubian army was guarded by exceptionally skilled archers. Some say the name Nubia also meant gold. Nubia was previously known as Kush. Many Nubians, mainly farmers lived along the banks of river Nile. They grew different grains, lentils etc. Their main measure of wealth and social status was their cattle. Nubians mined gold and carnelian in the deserts. Nubians traded cattle, carnelian, gold, incense etc., for grains, linen, vegetable oils, beer, wine etc. Mostly information about Nubia was gathered from rock arts, monuments and archaeological excavations. Nubia trade gold and elephant tusks with Egypt.