The correct option is: "He has been accused of gaining money illegally or suspiciously."
The Watergate scandal was a major political scandal that took place in the United States in the 1970s as a result of a theft of documents in the Watergate office complex in Washington DC, home of the National Committee of the United States Democratic Party, and the subsequent the Nixon administration's attempt to cover up those responsible. Because of this scandal and being cornered, Nixon tried to clean his good name and that's why he needed to say that he was not a thief. Which did not happen because he was put on trial for interfering in the judicial process, this proved his later resignation and disqualification to practice his profession (Lawyer) throughout the US territory.