Answer:
I would say B.
Explanation:
All the other answers are not very upfront and specific and don't really make sense. When a group of people are unified or are without conflict a societey will succeed. A good example of this is how aincient China had dynasties and how they all fell and was mainly because of conflict (being ununified).
Who will perform the duties of the president, if the president can't, is specified by the presidential line of succession.
After the president and vice-president, the next in line is the speaker of the House (answer c)
They determine which stories will receive public attention. Because the media has the power to focus the public's attention on a particular issue.