The data in the timeline best supports the conclusion that the united states supplied arms and gave others support to the allies in order to:
prop up insurgency groups with germany and italy
prevent the election of fascist leaders in germany and italy
combat the rise of military aggression from germany and italy
sponsor effects to spread democracy in germany and italy

Hi!

The correct answer would be Combat the rise of military aggression from Germany and Italy

Explanation

Over the timeline, we see Italy and Germany gradually expanding and imposing their rule over various areas after Hitler takes office as the fuhrer. Germany at that time had great military power, and along with Italy, the two were significantly powerful. Through this we can deduce that the US then supported the Allies by supplying them with arms after they had declared war against Germany in 1939 in hopes that the Allies would be able to defeat them.

Hope this helps.

the social contract theory