Question: The horse-collar tackle technique is most closely associated with a football player who played college football for what school?

Context paragraphs:
Rex Boggan: Rex Reed Boggan (March 27, 1930 - December 8, 1985) was an American football player.  Boggan was born in Tupelo, Mississippi, and attended the University of Mississippi.  He played college football at the tackle position for the Ole Miss Rebels football team.  He was selected by the Associated Press as a first-team player on its 1954 College Football All-America Team.  He was drafted by the New York Giants in the 20th round of the 1952 NFL Draft and played for the Giants during the 1955 season at the defensive tackle position.

Roy Williams (safety): Roy Lee Williams (born August 14, 1980), is a former American college and professional football player who was a safety in the National Football League (NFL) for nine seasons.  He played college football for the University of Oklahoma, and was recognized as a unanimous All-American.  He was drafted by the Dallas Cowboys eighth overall in the 2002 NFL Draft, and played professionally for the Cowboys and Cincinnati Bengals.  He earned five straight Pro Bowl selections from 2003 to 2007.  Williams is currently a sideline reporter for Oklahoma football games.

Bud McFadin: Lewis Pate "Bud" McFadin (August 21, 1928 – February 13, 2006) was an American football player.  He played college football at the University of Texas and was a unanimous selection at the guard position on the 1950 College Football All-America Team.  He later played professional football in the National Football League (NFL) for the Los Angeles Rams (1952–1956) and in the American Football League (AFL) for the Denver Broncos (1960–1963) and Houston Oilers (1964–1965).  A versatile player, he played tackle and linebacker on defense, as well as tackle and guard on offense.  He was a Pro Bowl pick in 1955 and 1956, a "Sporting News" All-AFL defensive tackle in 1960, 1961 and 1962, and an American Football League West Division All-Star in 1963.

Spike Nelson: Emerson William "Spike" Nelson (April 2, 1906 – October 20, 1998) was an American football player and coach.  He served as the head football coach at Mississippi State College, now Mississippi State University, in 1938 and at Yale University in 1941, compiling a career college football record of 5–13.  He played college football as a tackle at the University of Iowa and was selected as a first-team tackle by the "New York Sun" on its 1926 College Football All-America Team.  He was also selected as a second-team All-American by the Associated Press and Central Press.

Nick Mumley: Nicholas "Nick" Mumley, Jr. (born January 26, 1937) was an American football player.  He grew up in Wheeling, West Virginia, and attended Wheeling High School.  He then enrolled at Purdue University where he played college football at the tackle position for the Purdue Boilermakers football team from 1956 to 1957.  He was selected by the International News Service as a second-team player on its 1957 College Football All-America Team.  He later played professional football in the American Football League, appearing in 42 games as a tackle and defensive end for the New York Titans (later renamed the Jets) from 1960 to 1962.

Orland Smith (American football): Orland Francis Smith (November 5, 1905 – August 14, 1977) was an American football player.  He played at the tackle position in the National Football League (NFL) for the Providence Steam Roller from 1927 to 1929.  Smith was attending medical school at Boston University during the week while playing in the NFL on Sundays.  He also played college football at Brown University where he was selected by the Associated Press as a third-team player, and by "Collier's Weekly" as a second-team player, on the 1926 College Football All-America Team.

Horse-collar tackle: The horse-collar tackle is an American football maneuver in which a defender tackles another player by grabbing the back collar or the back-inside of an opponent's shoulder pads and pulling the ball carrier directly downward in order to pull his feet from underneath him.  The technique is most closely associated with Pro Bowl safety Roy Williams.  This kind of tackle was banned from the NFL during the 2005 off-season.  The rule forbidding it is often referred to in the press as "The Roy Williams Rule".  The rule, with modifications, was adopted in college football in 2008 and high school football in 2009.

Alvin Wistert: Alvin Lawrence "Moose" Wistert (June 26, 1916 – October 3, 2005) was an American football player.  A native of Chicago, Illinois, he played college football at the tackle position for Boston University in 1946 and at the University of Michigan from 1947 to 1949.  He began his collegiate football career at age 30 following 12 years of working in a factory and serving in the United States Marine Corps during World War II.  He played at the defensive tackle position for the undefeated 1947 and 1948 Michigan Wolverines football teams, both of which finished the season ranked No. 1 in the final Associated Press poll.  He also holds the distinction of being the oldest college football player ever selected as a College Football All-American, having been selected to the 1948 College Football All-America Team at age 32 and the 1949 Team at age 33.

Clyde Johnson: Clyde Elmer Johnson (August 22, 1917 – September 14, 1997) was an American football player.  He played college football for the Kentucky Wildcats football team and was selected by the Associated Press as a first-team tackle on the 1942 College Football All-America Team.  He was Kentucky's first All-American football player.  At six feet, six inches, and 269 pounds, he was one of the largest football players of his day.  He was drafted by the Cleveland Rams with the 35th pick in the 1943 NFL Draft, but his professional debut was delayed during World War II.  After the war, he played in the National Football League (NFL) for the Rams in 1946 and 1947 and for the Los Angeles Dons in 1948.  He died in 1997 in Orange County, California, at age 80.

Wesley Englehorn: Wesley Theodore "Moose" Englehorn (January 21, 1890 – September 3, 1993) was an American football player and coach.  Born in Helena, Montana, Englehorn first gained fame as a football player for Spokane High School.  While he was a junior in high school, he was reportedly recruited by Princeton University to come east to play football for the school.  A newspaper account in 1907 reported: "It is expected that Wesley Englehorn, the giant left tackle of the high school team, will also enter the Eastern college.  If this materializes the Spokane high school will be weakened next year by the loss of two of its greatest players.  ... Englehorn is also a strong basket ball player and track athlete."  Englehorn did not enroll at Princeton and instead played for two years on the All Star Pacific Northwest football and basketball teams.  He began his collegiate career at Washington State College.  After playing one year of football at Washington State, Englehorn enrolled at Dartmouth College, where he played two years at the tackle position.  He was elected team captain for the 1913 season, but he was declared ineligible under "the so-called three-year rule" because of his year at Washington State.  Though ineligible to play, Englehorn served as the team's assistant coach in 1913 and was elected class president.  He was selected as a first-team All-American in 1912.  He graduated from Dartmouth in 1914 and worked as a football coach for several years thereafter.  From 1914 to 1916, he was the football coach at Case School of Applied Science in Cleveland, Ohio.  In 1917, he was hired as the line coach and first assistant football coach at Colgate University.  In 1920, he was an assistant coach under Frank Cavanaugh at Boston College.  In 1921, he was hired as the head football coach at Amherst College.  In January 1922, Englehorn announced his retirement from coaching.  Shortly before his death at age 103, Englehorn said, "It's the football I remember best ... the teammates . .  the teamwork."  Prior to his death in 1993, he was living at Stapeley Hall, a home for the elderly in the Germantown section of Philadelphia, Pennsylvania, and was the oldest living All-American football player.

Supporting paragraphs: Horse-collar tackle Roy Williams (safety)
Answer: University of Oklahoma