A Chief Information Security Officer at a medium enterprise computer software company would be very likely to recommend Cisco Advanced Malware Protection for this reason: I feel that it gives me the features, the visibility, and the level of forensics that I need in my environment.
The answers is (c) bacteria-the simplest, smallest, and most abundant organisms on Earth. Bacteria are procaryotic organisms; which indicates a cellular structure lacking an organized nucleus and nuclear membrane.
1 A krill is about the size of your pinky.  Krill is possibly the most abundant species on the planet. In fact, it's estimated that the total weight of all Antarctic krill is more than the total weight of all humans on Earth!