It seems that you're asking about which industry has had the most significant impact on life in Southwest Asia. A common answer would likely be "oil" or "petroleum," as the oil industry has played a major role in the economic development and political landscape of many countries in the region.
So the complete sentence would be: "Income from the oil industry has affected life the most in Southwest Asia."
If you have other options in the drop-down menu, please provide them for a more precise answer.