The sheer bulk of data from the mass media seems to overpower us and drive us to ........ accounts for an easily and readily digestible portion of news.

The statement implies that with so much data and news to go around, we tend to favor a particular type of account for easily digestible portions.
Let's take a look at each option individually:
Option A: insular means narrow-minded, which would not be appropriate given the context of digestible news. 
Option B: investigative means an in-depth analysis filled with details, which goes against the idea of digestible news. 
Option C: synoptic means providing a summary that best aligns with the given idea. Since there is so much data, we are driven to synoptic accounts that provide summarized versions of this information.
Option D: Subjective here can be eliminated on the same basis as insular since that is not what the sentence is trying to say. 

Therefore, Option C is the correct answer.