Why Might It Be Easier to Determine the Bacterium That

Why might it be easier to determine the bacterium that caused pneumonia than one that caused a wound infection?

A) There are very few microorganisms that can cause pneumonia, while there are many that can cause wound infections.
B) The lungs are generally free of bacteria, while the skin may have a number of different types of bacteria on it. This could complicate identification processes for a wound infection, as bacteria normally found on the skin may be in the wound along with the particular bacterium causing the infection.
C) We have much better tests for bacteria in the lungs than we do in wounds.
D) The techniques of 16S rRNA sequencing are easier to perform on a sample taken from the lungs than a sample taken from a wound.