Final answer:
D. 99203. The code that should be used for a new patient who receives a chest x-ray and breathing treatment is 99203.
Step-by-step explanation:
The code that should be used for a new patient who receives a chest x-ray and breathing treatment would be 99203 (Option D). This code corresponds to a new patient visit with a detailed history, a detailed examination, and medical decision making of low complexity.
Codes 99204 (Option A) and 99205 (Option E) represent visits with a higher level of complexity and would not be appropriate for this scenario.
Codes 99214 (Option C) and 99215 (Option B) are for established patients and would not be applicable to a new patient visit.