You have been called to the scene of an 83-year-old woman with a high fever who reports chills and shortness of breath. She is tachypneic and showing signs of pain upon inspiration. You talk with her a bit and she seems confused of where she is, who she is, or who you are. Based on this presentation, the patient likely has:

A. tuberculosis.
B. croup.
C. pneumonia.
D. pertussis.​