Final answer:
Nelson Auto Services operates in the southwest region of the US and has service centers concentrated in that area.
Step-by-step explanation:
The subject of this question is Business. Nelson Auto Services is a company that operates in the southwest region of the US, as mentioned in the question. It has 16 service centers in various locations, indicating that the company has a presence in multiple areas within the region. Therefore, the correct option is D. Nelson Auto Services has service centers concentrated in the southwest region.