Question: Which son of Mary Williamson Averell served as Secretary of Commerce under President Harry S. Truman?

Context paragraphs:
W. Averell Harriman: William Averell Harriman (November 15, 1891July 26, 1986) was an American Democratic politician, businessman, and diplomat.  The son of railroad baron E. H. Harriman, he served as Secretary of Commerce under President Harry S. Truman and later as the 48th Governor of New York.  He was a candidate for the Democratic presidential nomination in 1952 and 1956, as well as a core member of the group of foreign policy elders known as "The Wise Men".

William Chrisman High School: William Chrisman High School is a high school located in Independence, Missouri, United States, as part of the Independence School District.  The school was founded in 1888 and was known as Independence High School.  The first building was located at the intersection of Pleasant and Truman Road, the current location of the Palmer/Central Office Building.  It is from this location that President Harry S. Truman, First Lady Bess Truman, and Truman White House Press Secretary and Pulitzer Prize winner Charles Griffith Ross graduated from in 1901.

William Chapman Foster: William Chapman Foster (April 27, 1897 – October 15, 1984) was an American businessman and high-ranking government official.  He served as United States Under Secretary of Commerce and United States Deputy Secretary of Defense under President Harry Truman.  Later, he served as the first United States Arms Control and Disarmament Agency director, under Presidents John F. Kennedy and Lyndon B. Johnson.

Harry S. Truman Historic District: The Harry S. Truman Historic District is a National Historic Landmark District encompassing sites closely associated with US President Harry S. Truman in Independence, Missouri.  It includes the Truman Home at 219 North Delaware, Truman's home for much of his adult life and now a centerpiece of the Harry S. Truman National Historic Site, and the Truman Presidential Library.  The district was listed on the National Register of Historic Places in 1971, and was designated a National Historic Landmark in 1974.  When first listed, the district included only the two buildings and a corridor joining them.  It was substantially enlarged in 2011 to include more sites and the environment in which Truman operated while living in Independence.

Truman College: Harry S Truman College, popularly called Truman College and formerly called Mayfair College, part of City Colleges of Chicago, a college that offers multiple 2-year associate degrees, as well as occupational training in a number of fields.  Located at 1145 West Wilson Avenue in the Uptown neighborhood, the school was named in honor of U.S. President Harry S. Truman, nominated for the vice presidency in the 1944 Democratic National Convention at the Chicago Stadium.  Nominated to join the Franklin D. Roosevelt Democratic ticket, Truman was a proponent of public colleges and universities.  Truman is the largest of the City Colleges of Chicago with a yearly enrollment of over 23,000 students, and has the largest English as a second language and GED program in Illinois.

Attempted assassination of Harry S. Truman: The second of two assassination attempts on US President Harry S. Truman occurred on November 1, 1950.  It was carried out by militant Puerto Rican pro-independence activists Oscar Collazo and Griselio Torresola while the president resided at Blair House during the renovation of the White House.  Both men were stopped before gaining entry to the house.  Torresola mortally wounded White House Police officer Leslie Coffelt, who killed him in return fire.  Secret Service agents wounded Collazo.  President Harry S. Truman was upstairs in the house and not harmed.

Margaret Truman: Mary Margaret Truman Daniel (February 17, 1924 –January 29, 2008), also known as Margaret Truman or Margaret Daniel, was an American singer who later became the successful author of a series of murder mysteries and a number of works on U.S. First Ladies and First Families, including a biography of her father, President Harry S. Truman.  The only child of Harry Truman and First Lady Bess Truman, she was "a witty, hard-working Midwestern girl with singing talent who was neither particularly pretty nor terribly plain."

Mary Williamson Averell: Mary Williamson Averell (July 22, 1851 – November 7, 1932) was an American philanthropist and the wife of railroad executive E. H. Harriman.  Born in New York to a successful family, Averell married Harriman in 1879.  Averell's father introduced Harriman to the railroad business.  After Harriman's death, his wife was left with between $70 and $100 million.  She became dedicated to philanthropy, donating the land that became Harriman State Park and largely funding the development of the controversial Eugenics Record Office.  Averell had several children; her son, W. Averell Harriman became governor of New York and her daughter Mary Harriman Rumsey founded the Junior League.

Truman Annex: Truman Annex is both a neighborhood and military installation in Key West, Florida, United States.  It is the part of the island that is west of Whitehead Street, with the exception of Bahama Village.  It is where the winter White House for President Harry S. Truman is located from its days as part of the former Naval Station Key West.  The Harry S. Truman Little White House in Key West, Florida was the winter White House for President Truman for 175 days during 11 visits.

United American Lines: United American Lines, the common name of the American Shipping and Commercial Corporation, was a shipping company founded by W. Averell Harriman in 1920.  Intended as a way for Harriman to make his mark in the business world outside of his father, railroad magnate E. H. Harriman, the company was financed by the younger Harriman's mother, Mary Williamson Averell.  Entering into the shipping world with little experience, Harriman's United American Lines entered into agreements with the Hamburg America Line (German: "Hamburg Amerikanische Packetfahrt Actien Gesellschaft" or ), which was determined to recover after the financial disaster that befell the German company as a result of World War I.

Supporting paragraphs: Mary Williamson Averell W. Averell Harriman
Answer: W. Averell Harriman