单项选择题 The Watergate Affair, the political espionage scandal, finally led to the resignation of President ______ in 1974.

单项选择题 Question 6 is based on the following news. At the end of the news item, you will be given 10 seconds to answer the question. Now listen to the news.

单项选择题 President Lincoln's ______ was to free black slaves in the south in American history.