A) to reduce disease transmission among domestic animals
B) to increase the growth rate of domestic animals
C) to reduce the likelihood of drug resistance
D) All of the above are correct.
E) Both "a" and "b" are correct.

A) when a patient is infected with an unknown pathogen
B) when the patient is immunocompromised
C) when antibiotics are being used prophylactically
D) when an infection is in a well-oxygenated region of the body
E) when Gram-negative bacteria have infected an ordinarily sterile region of the body

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