A 55-year-old Caucasian female with a history significant for RA presents to your office complaining of sharp localized pain under her right breast with each breath. On exam, her breath sounds are...

A 55-year-old Caucasian female with a history significant for RA presents to your office complaining of sharp localized pain under her right breast with each breath. On exam, her breath sounds are muffled at the right base and percussion is dull at the right base as well. The presence of neutrophils on fine needle aspiration confirms your diagnosis of which of the following?

A. Lobar pneumonia

B. Interstitial pneumonia

C. Pneumothorax

D. Pleural effusion