One of the Most Important Uses of the Gram Stain

One of the most important uses of the Gram stain of expectorated sputum received for routine bacteriologic culture is

A) to give the physician a quick analysis of the type of organism causing the infection.
B) to evaluate the quality of the specimen.
C) to distinguish between the possibility of bacterial or viral source of infection.
D) to begin appropriate antimicrobial therapy as soon as possible.