The primary goal of most media is to their audience.
a. persuade
c. harm
b. inform

The primary goal of most media is to inform their audience. The correct option among all the options that are given in the question is option "b". Although this is the primary goal of the media, but it is often seen that the media becomes partial while reporting a news and this can be very harmful for the society.

The primary goal of most media is to inform their audience - b. 

Although many would say that the correct answer in this case would be A - persuade. It is actually true that the media wants to inform people of what has happened.