I feel this.

This is a tricky one because of the specificity involved! We have to remember that according to the syllabus, ants of most species use pheromones - most but NOT all. This means that some ants species DO NOT use pheromones. C is about ants that only forage for food in the afternoon - if pheromones are ineffective at this time, why would they use them? Surely they must have a different method for collecting food to ensure survival. It follows that C is correct. E is a highly attractive incorrect answer choice but we don't know anything about the efficiency of ants that use pheromones versus those who do not. It would be wrong to assume that pheromone-using ants are more efficient only because the stimulus is about them.

I read D many, many times only to conclude that it doesn't make sense after "or not!"

I thought that this whole sentence was about the politicians resorting to personal attacks; this is what editorialists make of them (criticize) and this is what voters make of them (disregard). Coupled with the following sentence, I understood the context to explain that this is an election tactic that is not to be taken seriously which would explain why "most voters pay them scant attention." Why make this argument (that political commentators not be excused for mudslinging) if voters pay scant attention to them to begin with (in the case that the "them" referred to the editorialists)?