Which best describes how social-networking sites political campaigns, especially when compared to traditional media? they allow supporters to publicly criticize opponents. they ensure that a campaign’s message reaches a large audience. they enable campaigns to sample public opinion. they facilitate clear communication.

The correct option is THEY ENABLE CAMPAIGNS TO SAMPLE PUBLIC OPINION. The question is asking for comparison between traditional media and social networking sites. Traditional media do not have facilities  or means of allowing the public to give feedback on campaigns in contrast to social networking sites which allow people to publicly express their opinions about public matters. Public opinions on campaigns can help the campaigners to make necessary adjustments that will ensure success.