What is important when looking at a historical source

Which of the following is not true of television journalism? television is even more effective than the radio as an agency for influencing public opinion. you must pay millions of dollars to build up and project the proper television image for their candidates. television media performs a public service in the field of political education. we should form our opinions by listening to network commentators to get a well-rounded perspective, as you can assemble from different sources we should listen to more than one commentator and read background articles in boo and magazines