Final answer:
The correct answer is option c) Informational.
Step-by-step explanation:
The Pentagon Papers, released in 1971, are an example of informational forms of influence. By providing previously undisclosed details about the U.S. government's actions and intentions in Vietnam, the papers informed the public about the real circumstances of the war, contrasting with the official narratives presented at the time. The leak of these documents had a considerable impact on the public's perception of the government and contributed to a larger debate on transparency and accountability in governance.
In the context of the Pentagon Papers, informational social influence occurs when individuals accept information from another as evidence about reality. The papers provided facts that the American public used as a basis to reassess their beliefs about the Vietnam War, demonstrating how information can lead to a transformation in attitudes and perspectives. These revelations were further validated by the Supreme Court case New York Times Co. v. United States, which reinforced the principle of a limited government capability to impose prior restraint on the media, thereby upholding First Amendment rights.