Answer:
b) An obligate parasite that cannot survive outside the lungs.
Explanation:
Pneumocystis jirovecii:
This is the fungus which belongs to genus Pneumocystis. Pneumocystis jirovecii is the obligate protozoan extracellular parasite that causes disease known as Pneumocystis pneumonia.
Lifecycle:
Life cycle of any specie which belongs to the genus Pneumocystis is not known. Reason behind this mystery is that its all stages are present in lungs and cannot cultured in the vivo medium. Its direct observation in difficult.
Correct Choice:
b) An obligate parasite that cannot survive outside the lungs.