What is the main reason that the Blue Ridge Mountains have been
important to the growth of Georgia?
A, The rich red clay soil is excellent for agriculture.
B. Precipitation in the mountains provides water to the entire state.
C. Natural passes through the mountains established trade routes to
the Midwest.
D. They form a natural barrier between the coastal plain and the
Piedmont region.

B, Precipitation in the mountains provides water to the entire state.

Explanation:

The water that the mountains collected was used to sustain the agricultural economy In Georgia. Combined with their warm weather and fertile soil, Georgia became the major agricultural producer in north America.

As per today, Agricultural production contributed  over $ 70 Billion to Georgia's economy (which is around 10%) of their overall economy.