Which statement best explains the purpose of the case the United States v. Nixon?

The case was to prosecute members of the White House for connection to the leaking of the Pentagon Papers.
The case was to secure President Nixon’s recordings for purposes of investigating the Watergate break-ins.
The case was to impeach President Nixon for abuses of power based on the Watergate cover-up.
The case was to prosecute President Nixon for the purposes of recuperating losses to the government.