Final answer:
The correct answer is a. Advocates for a worldwide reduction in army sizes, as there is explicit mention of advocating for a reduction in armaments to prevent nations from acts of aggression.
Step-by-step explanation:
The question likely relates to historical perspectives on military sizes and policies. From the information provided, it seems that there are varied historical contexts in which army sizes were significant, such as during World War I and specific army projections for the future. Based on the reference to "freedom from fear" which translates into a worldwide reduction of armaments, the most accurate answer would be: a. Advocates for a worldwide reduction in army sizes.
Throughout history, nations have mobilized large armies to ensure military success and security, yet there has also been advocacy for the reduction of armaments globally. For instance, during World War I, the United States expanded its army size through a massive recruitment and draft program to aid in the war effort. In more contemporary terms, with the advent of new technologies such as AI, there are discussions about the future of armies like the 'Army 2040' project.
The quote explicitly mentioning the reduction of armaments globally supports the idea that the aim is to prevent nations from committing acts of aggression against each other, which aligns with the concept of seeking a reduction in army sizes globally.