The introductory passage described a consortium consisting of ANME and a sulfur oxidizing bacteria. Which of the following would be important considerations in choosing the best technique to determine the number of living cells in a culture of the consortium?

Select the best answer.

A) Some fluorescent stains react differently based upon whether a cell has an intact cell membrane.
B) Phylogenetic stains can distinguish between species of Bacteria and species of Archaea.
C) DAPI can be used to stain DNA.
D) Cells present in low concentrations can be counted using microscopic cell counts, but they must be concentrated first.
E) Small cells are more difficult to see when doing microscopic cell counts.