Answer:
B: International law versus an act of war
Explanation:
The main focus of this passage from Franklin D. Roosevelt's speech is to make it clear to the world that aiding allied democracies against threats from dictators is not a breach of international law, neither is it an act of war. And that The USA will not be intimidated by dictators even if they consider this aid an act of war, or breach of international law.
So, considering the main focus and topic of the passage the theme of this passage is international law versus an act of war.
There is just a minute hint to use of force (proper or improper), and peace and enemy's aggression. so these can't be the regarded as the passage's theme. Similarly, although there is mention of dictators, yet it is not stressed.
