Why Can Direct Microscopy Not Be Used to Provide a Presumptive

Multiple Choice

Why can direct microscopy not be used to provide a presumptive identification of the enteric bacteria?

A) Some members of the genus Gram stain weakly.
B) The microscopic characteristics are indistinguishable from other gram-negative bacteria.
C) Some members of the genus do not decolorize well and appear gram-positive.
D) Some members have very thick capsules, and these do not allow the penetration of the Gram stain.