Final answer:
Military and medical spending in the United States share a commonality in the substantial funds allocated to research and the presence of considerable fraud within both sectors.
Step-by-step explanation:
The commonality between military and medical spending in the United States isn't that those in the military receive the best medical care, nor is it that the U.S. spends very little in both categories, or that there's nothing in common as they are very different categories of spending. Instead, the correct answer is 'c. a lot is spent on research, and there is considerable fraud.'
In both military and healthcare sectors, there is a significant investment in research and development to advance respective fields. Unfortunately, both sectors also face issues with fraud, where funds are misused or misallocated. Strategies such as fee-for-service in healthcare can lead to unnecessary medical spending, while complex military contracts present opportunities for fraudulent activities.