President Nixon resigned his office, otherwise, he was going to be impeached. So, option C is correct.
Richard Milhous Nixon was an American politician who served as the 37th president of the United States from 1969 until 1974, when he resigned from office, becaming in the only U.S. president to do so.
By late 1973, the Watergate scandal increased, costing Nixon much of his political support.
By resigning he claimed in an address from the Oval Office: “By taking this action,” “I hope that I will have hastened the start of the process of healing which is so desperately needed in America.”