World War II required Oklahoma to develop military and aviation industries, which diversified its economy. Previously, the state was economically dependent on unstable __________ markets.

Before World War II, Oklahoma’s economy relied heavily on agriculture and petroleum, both of which could be affected by changing prices and demand. The war encouraged growth in military and aviation industries, diversifying the economy beyond those two unstable markets. Therefore, “agriculture and petroleum” is the correct choice.

AI-written and checked against the verified answer.