Which of the following presidents was assassinated while in office?
a) grover cleveland
b) james monroe
c) harry s. truman
d) william mckinley

The correct answer is D. William McKinley was assassinated while in office.

Explanation:

William McKinley was the twenty-fifth president of the United States, and the last veteran of the Civil War who reached that position.

During the 1880s he was an important member of the Republican Party. As a congressman, he was responsible for the increase in import tariffs (McKinley Tariff), as a measure of prosperity. In his candidacy for the presidential elections of 1896 he promoted pluralism among ethnic groups. His campaign was designed by Mark Hanna, who introduced new advertising techniques that revolutionized political campaigns, and defeated Democrat William Jennings Bryan. With his mandate began a period of republican domination, in which the commercial activity was promoted. The United States also became a world power after its victory in the Spanish-American War. This allowed McKinley to be elected president again in 1900 after another intense campaign also against Bryan. Regarding international politics, he supported the independence of Cuba; the war with Spain gave the United States control of Puerto Rico, Guam and the Philippines.  

On September 6, 1901 he was shot by anarchist Leon Czolgosz. He died eight days later and became the third president killed in office, after Abraham Lincoln and James Abram Garfield. He was succeeded by Theodore Roosevelt.

uhh idk for sure but i think it makes it difficult to pump the oil through the oil rigs