All of the Following Can Make Interpreting the Gram Stain

Multiple Choice

All of the following can make interpreting the Gram stain difficult except

A) testing bacteria that are forming endospores.
B) the culture is between 24 and 48 hours old.
C) testing bacteria with especially resistant cell walls.
D) testing bacteria that have a waxy cell wall.
E) the culture is more than 48 hours old and contains damaged cells.