A 2-year-old patient presents to the urgent care with a chief complaint of "runny nose." Physical examination reveals purulent drainage from the left nostril that is foul-smelling; nasal mucosa is swollen and erythematous. The TMs are clear bilaterally, and oropharynx is normal. The rest of the exam is unremarkable. The NP suspects:
A. Maxillary sinusitis
B. Rhinosinusitis
C. Nasal foreign body
D. Allergic rhinitis