As a result of Greece's rocky soil A. The people of ancient Greece became reliant on the sea for fish and trade routes to get what they needed.
B. Other civilizations refused to trade with Greece.
C. The Greeks chose to move to a better geographic location.
D. The Greeks chose to wear lightweight clothing in order to adapt to their climate.

I believe it's "A. The people of ancient Greece became reliant on the sea for fish and trade routes to get what they needed."

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.