D. The lend-lease act.
Passed in 1941 rhe leand lease act provided the president with the faculty to lend or lease arms or money from the Us budget to any country whose defense the president the President deems vital to the united states.
Which basically meant that the US was not actually at war, but could lend money or weapons to the countries that were at war and whose sovereignty was vital to the well being onf the United States, with this the government of the States picked a side on WWII agaisnt the axis.