How Does the Role of the National Organization Today Differ

How does the role of the national organization today differ from its role in previous decades?

A) National party organizations used to have a hands-off approach to presidential campaigns, but are now more involved in coordination and advising a candidate.
B) National party organizations used to play a larger advisory role in presidential campaigns, but now provide more of a supportive role.
C) National party organizations used to have greater influence over voters, but social media has decreased that influence.
D) National party organizations used to choose and support presidential candidates, but have become more symbolic and serve few real functions now.