About Pneumocystis pneumonia the true statement is:
Pneumocystis jirovecii is a fungus responding to Cotrimoxazole. It causes opportunistic pneumonia in patients with HIV infection. 
The most common radiology finding is a normal X-ray chest.  However, the most typical X-ray is  a bat wing distribution of infiltrates with pneumocysts in peripheral fields. 
Steroids are combined with Cotrimoxazole in treatment of severe Pneumocystis jirovecii pneumonia.
The causative organism is a protozoan
Drug of choice is Trimethoprim-Sulfamethoxazole (Cotrimoxazole)
Most common radiological appearance is a bat wing distribution of infiltrates with pneumocysts in peripheral fields
Steroids have no role in the therapy of Pneumocystis pneumonia