The correct answer is A. Watergate Scandal.
This scandal involved President Richard Nixon and a break-in at the Democratic National Convention headquarters. It was rumored that Nixon was involved with this break-in, in the sense that he helped to arrange it. Due to the investigate reporting of Carl Bernstein and Bob Woodward, the corruption of Nixon's administration became public knowledge. Ultimately, this lead to the resignation of President Nixon, who is the only US president to ever resign from the position.