Which of the following Presidents of the United States was assassinated?

William McKinley was the president of the United States who was assassinated. On September 6, 1901, McKinley was shot by an anarchist named Leon Czolgosz while attending the Pan-American Exposition in Buffalo, New York. McKinley was greeting well-wishers when Czolgosz approached him with a concealed handgun and fired two shots, fatally wounding the president. Despite efforts to save him, McKinley succumbed to his injuries on September 14, making him the third U.S. president to be assassinated in office.