FCEM-0583

A 65-year-old man presents with cough and shortness of breath. His sputum is rusty in colour and is suffering from a fever. Upon examination, it was noted that he has crackles in the right upper lobe. A chest X-ray showed the presence of a right upper lobe cavitation.

Among the following microorganisms, which is considered to be mostly associated with a cavitating upper lobe pneumonia?