Answer:
C) the extent to which the separation of powers was allowed
Step-by-step explanation:
The United States v. Nixon was a case in which Richard Nixon (The President at the time) was accused of being involved in the Watergate Scandal (1972). In the Court, the Supreme Court ordered him to deliver the unedited tape recordings and documents related to such event. However, Nixon refused to do so, claiming his "Executive Privilege", that is to say, his right as President to withhold information from other government branches to preserve confidential communications within the executive branch or to secure the national interest.
The constitutional issue at the heart of the case was the extent or scope of the powers of the executive and the judicial. Did the President have the power to withhold information and not show it to the other branches, and until what point? And did the Judicial have the power to order him to deliver such "confidential" documents?
At the end of the case, the result did not favor the President as the Court determined that the executive privilege had limits and it wasn't immune from judicial review, regarding the demands of due process of law, and he had to show the evidence.