He wanted to build up the nation's army and navy is the statement among the statements given in the question that was one of the policy changes Thomas Jefferson made when he became president. The correct option among all the options given in the question is the last option or option "D".
European Countries invade African Resources
The build up of the us military in 1916 was an example of : D. Preparedness
Which means that it's the period where U.S military took many precautions/measures to face potential threat or disaster from outside
hope this helps
