The answer is: E. It became a military superpower in the world but lacked a strong economy.
During the 20th century, United states more than 20% of its GDP to be allocated into millitary spending, which make us able to become a millitary superpower and contribute greatly to the victories during the world war I.
There is a downside to this. Large allocation to millitary budget means that there would be less that can be allocated to build things such as infrastructures, loans, government sponsored jobs, etc. Which is why the economy of united states at that era was a little bit lacking.
Http://www.dummies.com/education/history/american-history/american-preparation-for-world-war-ii/
You're welcome xP
The correct answer is Albert Einstein.
Albert Einstein urged President Franklin D. Roosevelt to speed up the process of developing an atomic bomb because of his knowledge regarding Germany's advancement towards the development of this weapon. Einstein was worried that the Germans would be able to develop this weapon before the US, which would result in catastrophic damage to the entire world.