In which of the following situations might a broad spectrum drug be preferable to a narrow spectrum drug?

A) when the patient is infected with an unknown pathogen
B) when the patient is immunocompromised
C) when Gram-negative bacteria have infected an ordinarily sterile region of the body
D) in a well-oxygenated region of the body
E) when the patient is in danger of going into shock from endotoxin poisoning