My first post in this forum
I think the answer should be A.
Lets read the stimulus again.
First sentence means:
The public is aware of the possibility of biases
(note: plural) in the mass media and distrusts the media as too powerful.
Eg: Lets say one newspaper says Mr. TomBanks sucks as an actor. Another paper says Mr. TomBanks is okay. The third paper say Mr.TomBanks is excellent.
We have 3 biases here about the same topic.
Now for the second sentence:
The body of information against which the public evaluates the plausibility of each new media report comes, however, from what the public has heard of through the mass media.
In simple English. this means the public has a database of information regarding TomBanks, thanks to the three newspapers in our example. If a fourth newspaper were to say TomBanks is a good actor, the public would compare this new information with the new information in the database, and the public might come to the conclusion that, since two newspapers say TomBanks is good, he may be good (note: may be and not "is") and that the other two papers must be biased.
Now let us take the option A.
If there is a pervasive bias
(note: singular) in the presentation of news by the mass media, it would be hard for the public to discern that bias.
Going back to Mr.TomBanks. Lets suppose Mr.TomBanks wields enough clout with the three editors of the respective newspapers, and hence, the editors see to it that all of their newspapers say "Mr.TomBanks is a good actor" even though he sucks as an actor. Now if the fourth editor also happens to be a friend of Mr.Banks, and give a glowing report on the abilities of Mr.Banks, the public would find it hard to discern/evaluate if the new (fourth) information is correct as their database shows good/good/good by all the previous three newspapers.
E is wrong because it goes to the extreme and says people are predisposed to believe a news item when a news item contradicts a stereotype. The passage only says that public is aware of biases, nothing of its predispositions.
The surest sign that there is intelligent life out there is the fact that they have not tried to contact us.