Background: Robert Leland Eubanks (born January 8, 1938) is an American disc jockey, television personality and game show host, best known for hosting the game show The Newlywed Game on and off since 1966. He also hosted the successful revamp version of Card Sharks from 1986 to 1989. Eubanks received a star on the Hollywood Walk of Fame for his television work in 2000. The star is in front of Grauman's Egyptian Theatre, where Eubanks worked during the first years of his broadcasting career.
Context: In 1966, he received a phone call from Chuck Barris to host a new game show, The Newlywed Game, which premiered on ABC that same year. During its debut, it was an immediate hit, and the show's popularity led the network to expand the prime-time lineup, where it had run on the air for five years. Only 28 years old when he started hosting, Eubanks became widely popular for bringing a youthful energy to daytime television, pressing contestants into giving embarrassing and hilarious answers. The Newlywed Game was also ranked as one of the top three daytime game shows, for five consecutive years, between 1968 and 1973, and was ranked in the top three prime-time game shows, also for five years, between 1966 and 1971.  While hosting The Newlywed Game, Eubanks was known for using the catchphrase "makin' whoopee", in reference to marital sexual intercourse. It was Eubanks who coined the term from the song of the same name, in an attempt to keep parents with young children from the need to explain the facts of life because of a television show. While his network was comfortable with the term "making love", they did not allow the use of the word "panties".  While not taping, he also pursued a career in the country music business, where he served as manager of such artists as Dolly Parton, Barbara Mandrell and Marty Robbins. The same year, he also signed Merle Haggard to an exclusive live-performance contract, producing more than 100 dates per year with the performer for almost a decade. His first ending of his first-run network TV show, The Newlywed Game, ended in 1974, after 2,195 episodes, making Eubanks one of the most beloved and bankable game show hosts to date. He also hosted various editions in syndication, from 1977-1980, 1985-1988 and 1997-1999. For Series Two of the 2009 GSN revival, Eubanks hosted a celebrity charity episode with first host Carnie Wilson and her husband Rob Bonfiglio playing against Carnie's sister Wendy and her husband Daniel Knutson, and their mother Marilyn Wilson-Rutherford and her current husband Daniel Rutherford. In spring 2010, Eubanks hosted another episode of The Newlywed Game, subtitled the "Game Show Kings" episode. This episode featured Monty Hall and his wife Marilyn Hall, Peter Marshall and his wife Laurie Stewart, and Wink Martindale with his wife Sandy. This makes him the only person to host the same game show in six consecutive decades (1960s, 1970s, 1980s, 1990s, 2000s and 2010s).  In 1988, Eubanks left The Newlywed Game to pursue other interests (even though he was still hosting Card Sharks on CBS for another seven months) and was replaced by Paul Rodriguez.  In 1996, Eubanks also appeared as the host of Prime Time Country.
Question: who did he manage?. Whats the answer?
Dolly Parton, Barbara Mandrell and Marty Robbins.