The Phylogenetic Species Concept May Not Be Useful for Microbial

The phylogenetic species concept may not be useful for microbial species because

A) microbes are not neatly divided by species barriers.
B) it is only useful if organisms reliably pass down genes to offspring.
C) the genomes of microbes are mixed together by horizontal gene transfer, resulting in a mosaic-like genome.
D) all of the above