Quoc: William Henry Harrison Sr. (February 9, 1773 -- April 4, 1841) was an American military officer, a principal contributor in the War of 1812, and the ninth president of the United States (1841). He was the last president born before the American Revolution, and died of pneumonia just 31 days into his term, thereby serving the shortest tenure in United States presidential history. He was the first president to die in office, and his death sparked a brief constitutional crisis. Its resolution left unsettled Constitutional questions as to the presidential line of succession until the passage of the Twenty-fifth Amendment to the United States Constitution in 1967. Harrison was a son of Founding Father Benjamin Harrison V and the paternal grandfather of Benjamin Harrison, the 23rd United States President (1889 -- 1893).

Answer this question based on the passage: who was the president that served the shortest term?
HW Chung: OK, some thoughts:
The relevant information is: He was the last president born before the American Revolution, and died of pneumonia just 31 days into his term, thereby serving the shortest tenure in United States presidential history. The answer is William Henry Harrison Sr..