Inflammation of the lung caused by bacteria,viruses,or chemical irritants is:

A) croup.
B) stridor.
C) pertussis.
D) pneumonia.

Pneumonia

An infection that inflames the air sacs in one or both lungs, which may fill with fluid or pus, causing cough with phlegm or pus, fever, chills, and difficulty breathing.

Pertussis

Also known as whooping cough, a highly contagious respiratory tract infection characterized by severe coughing fits.