Question: Henry Patrick "Hank" Egan Jr., is a professional basketball coach in the National Basketball Association, he has also been an assistant with the San Antonio Spurs, to which American basketball coach who is currently the head coach of the San Antonio Spurs?
Context: The Big Three were a trio of basketball players for the San Antonio Spurs of the National Basketball Association (NBA) from 2002–2016.  The Big Three consisted of Tim Duncan, Tony Parker, and Manu Ginóbili.  Each player of the Big Three was drafted by the San Antonio Spurs and played their entire NBA careers with the San Antonio Spurs.  The Big Three won four NBA Championships during their time together in San Antonio, in 2003, 2005, 2007, and 2014.  The trio is widely regarded as the greatest trio of teammates in NBA history, as they have won over 1,000 games together. Patrick Sammy Mills (born 11 August 1988) is an Australian professional basketball player for the San Antonio Spurs of the National Basketball Association (NBA).  Mills is the second Indigenous Australian to play in the NBA (after Nathan Jawai) and is of Torres Strait Islander descent.  Mills was drafted by the Portland Trail Blazers with the 55th overall pick in the 2009 NBA draft after playing college basketball for Saint Mary's College of California.  He also played for the Melbourne Tigers of the National Basketball League and the Xinjiang Flying Tigers of the Chinese Basketball Association during the NBA lockout.  He signed with the San Antonio Spurs in 2012 and won an NBA championship with them in 2014.  He plays the point guard position. William Anthony Parker Jr. (born 17 May 1982) is a French professional basketball player for the San Antonio Spurs of the National Basketball Association (NBA).  The son of a professional basketball player, Parker played for two years in the French basketball league before entering the 2001 NBA draft.  He was selected by the San Antonio Spurs with the 28th overall pick in the draft and quickly became their starting point guard.  Parker has won four NBA Championships (2003, 2005, 2007, and 2014), all of which were with the Spurs. Gregg Charles Popovich (born January 28, 1949) is an American basketball coach who is currently the head coach of the San Antonio Spurs of the National Basketball Association (NBA).  Taking over as coach of the Spurs in 1996, Popovich is the longest tenured active coach in both the NBA and all US major sports leagues.  He is often referred to as "Coach Pop" or simply "Pop." Johnny Earl Dawkins Jr. (born September 28, 1963) is an American basketball coach and former player who is the head coach for the UCF men's basketball team.  From 2008–2016, he was the head coach of Stanford.  He was a two-time All-American and national player of the year as a senior in 1986 at Duke from 1982–1986.  Dawkins subsequently played nine seasons in the National Basketball Association (NBA) with the San Antonio Spurs (1986–1989), Philadelphia 76ers (1989–1994), and Detroit Pistons (1994–1995).  From 1998 to 2008, he served as an assistant basketball coach at his alma mater, Duke. Dennis Alan Felton (born June 21, 1963) is an American basketball coach, currently the head coach at Cleveland State University.  He is the former head men's basketball coach at the University of Georgia and at WKU, and also served as a player personnel assistant for the National Basketball Association's San Antonio Spurs. Spurs Sports & Entertainment L.L.C. (SS&E) is a San Antonio, Texas based sports & entertainment organization.  The company owns and operates several sporting franchises including the 5-time National Basketball Association (NBA) champions San Antonio Spurs, the Women's National Basketball Association (WNBA)'s San Antonio Stars, AHL's San Antonio Rampage, NBA G League's Austin Spurs, and the USL club San Antonio FC.  SS&E also operates the Bexar County owned multi-purpose facility, AT&T Center. Henry Patrick "Hank" Egan Jr. (born August 17, 1937) is a professional basketball coach in the National Basketball Association.  He has most recently served as an assistant coach for the Cleveland Cavaliers (to Mike Brown).  He has also been an assistant with the Golden State Warriors (to Eric Musselman) and San Antonio Spurs (to Gregg Popovich). The San Antonio Spurs are a professional basketball team based in San Antonio that competes in the National Basketball Association (NBA).  They were founded in Dallas, Texas as the Dallas Chaparrals, one of the eleven charter franchises of the American Basketball Association (ABA), in 1967.  During the 1970–71 season, in an attempt to make the team a regional one, the name "Dallas" was dropped in favor of "Texas" and some home games were played in Fort Worth and Lubbock, but low attendance figures prompted the team to return full-time to Dallas the following season.  In 1973 the franchise relocated to San Antonio and was renamed the San Antonio Spurs.  Three years later the Spurs were one of four ABA franchises who joined the NBA as a result of the ABA–NBA merger. The San Antonio Spurs are an American professional basketball team based in San Antonio, Texas.  They are a member of the Southwest Division of the Western Conference in the National Basketball Association (NBA).  The franchise was founded as the Dallas Chaparrals of the American Basketball Association (ABA) in 1967.  The team suffered from poor attendance and general disinterest by fans in Dallas, and the name "Dallas" was dropped in favor of "Texas" during the 1970–71 season in an attempt to make the team regional.  This also proved to be a failure, and the team returned full-time to use "Dallas" for the 1971–72 season.  The team was put up for sale after missing the playoffs in the 1972–73 season.  The team was acquired by a group of 36 San Antonio businessmen, led by Angelo Drossos and Red McCombs, who relocated the team to San Antonio, Texas and renamed it to Spurs.  In 1976, the ABA folded, threatening the future of San Antonio's sole professional sports franchise.  The NBA, however, decided to admit four ABA teams into the league, including the Spurs, along with the Denver Nuggets, the Indiana Pacers and the New York Nets.
Answer: Gregg Charles Popovich