Final answer:
Luxembourg is the NATO country most likely to contribute the least to the annual NATO budget due to its smaller economy compared to other member nations like the United States, Germany, or France.
Step-by-step explanation:
The NATO country most likely to make the smallest total contribution to the annual NATO budget is Luxembourg. While NATO requires each member country to contribute to its funding and operations, the amount each country pays is linked to the size of its economy. The United States and Germany, as the two wealthiest NATO countries, each pay a significant portion of the operating costs, specifically 16 percent. Luxembourg, by contrast, has a much smaller economy compared to the other NATO members. Given that contributions are based on the ability to pay, represented through a percentage of each member's GDP, and the size of a country's economy, Luxembourg, with a significantly smaller economy, contributes less to the NATO budget than larger countries like the United States, Germany, or France.