The investments in foreign industries would not boost the economy of any country. In order to lift the economy, countries need to focus on their own internal market. The other options are all inside policies that eventually will lead to boost the American economy.
The southern United States had the highest percentage of slaves. I am not sure what time period you are talking about but I assume you mean in the United States.
Explanation: The newly passed Law of April 6, 1830, prohibited the entrance of Anglo-Americans into Texas unless they had a passport to Austin's or DeWitt's colony.
