c) William Henry Harrison

William Henry Harrison was the first American president to die in office. Elected as the 9th President of the United States, Harrison’s presidency was short-lived; he died just 31 days after his inauguration in 1841. His death marked the first presidential succession crisis in U.S. history and raised questions about the constitutional process for presidential succession. Harrison’s death underscored the importance of having clear procedures for such situations, eventually leading to the adoption of the 25th Amendment. His brief tenure and untimely death remain a notable part of American presidential history.