Answer:
b
Explanation:
The correct answer would be 6.4 x cells/ul.
For 1 x 10-6 dilution, the plating factor is . To find the number of bacteria in the original sample, the plating factor is multiplied by the colony count per ul.
<em>Number of viable bacteria = plating factor x colony count/ul</em>
Since 10 ul gives 64 colonies. 1 ul will give:
64/10 = 6.4 colonies.
Therefore, the viable bacteria in the original sample = 6.4 x cells/ul
The correct option is b.