What was the policy to diversify the South's economy by adding
industry to the economy's agricultural base called?

   The policy of diversifying the South's economy by adding industry to the economy's agricultural base ... political party that called for better schools, roads, changes in state tax laws, fair railroad rates, and government backed loans for farmers

Explanation:

a.

congress passed laws allowing for free passage between states.

hello!

according to the passage the most suitable options are two. the first one is "by leading the aef to victory in several key battles" like the battle of saint- mihiel and the battle of cantigny mentioned in the passage you copied here. the second one is "by the aef and allied forces defeat germany" since the passage says that his army destroy the german resistance in the meuse- argonne offensive. and also, "by insisting that the aef operate as an independent force".

hope this