Question: The Spectrum Song was the signature song of the uncle of who?

full_context: Document 1: An Adventure in Color/Mathmagicland: "An Adventure in Color/Mathmagicland" was the first color episode of Disney's long-running anthology series to air in color, premiering on September 24, 1961 as "Walt Disney's Wonderful World of Color" following the series' move from ABC to NBC. This show introduced a new character, Ludwig Von Drake, who provides an interesting lowdown on color (at one point performing "The Spectrum Song", all about different colors). By the end of the song, the NBC Peacock makes a brief cameo as a "color show-off". The kaleidoscopic intro to the show featured music composed by Richard M. Sherman and Robert B. Sherman. The second part of the show is the 1959 featurette "Donald in Mathmagic Land".
Document 2: Uncle Scrooge: Uncle Scrooge (stylized as Uncle $crooge) is a comic book starring Scrooge McDuck ("the richest duck in the world"), his nephew Donald Duck, and grandnephews Huey, Dewey, and Louie, and revolving around their adventures in Duckburg and around the world. It was first published in Four Color Comics #386 March 1952, as a spin-off of the popular "Donald Duck" series and is still presently ongoing. It has been produced under the aegis of several different publishers, including Western Publishing (initially in association with Dell Comics and later under its own subsidiary, Gold Key Comics and its Whitman imprint), Gladstone Publishing, Disney Comics, Gemstone Publishing, Boom! Studios, and IDW Publishing, and has undergone several hiatuses of varying length. Despite this, it has maintained the same numbering scheme throughout its six decade history, with only IDW adding a secondary numbering that started at #1.
Document 3: The Sherman Brothers Songbook: The Sherman Brothers Songbook is a compilation album of songs written by composer-lyricist duo Richard M. Sherman and Robert B. Sherman. It includes the Sherman Brothers' work for Disney as well as their non-Disney output. It was released on CD on October 13, 2009.
Document 4: Scrooge McDuck: Scrooge McDuck is a fictional character created in 1947 by Carl Barks during his time as a work-for-hire for The Walt Disney Company. Scrooge is an elderly Scottish anthropomorphic Pekin duck with a yellow-orange bill, legs, and feet. He typically wears a red or blue frock coat, top hat, pince-nez glasses, and spats. He is portrayed in animations as speaking with a Scottish accent.
Document 5: The Son of the Sun: "The Son of the Sun" is the first Scrooge McDuck comic by Don Rosa, first published in 1987. It is a well-known comic book story that features Disney's Scrooge McDuck, Donald Duck, and Huey, Dewey, and Louie, most notable for establishing Don Rosa as a major talent in the Disney comic book industry, as well as fulfilling Rosa's childhood dream of becoming a writer and illustrator of stories featuring Scrooge McDuck.
Document 6: Richard M. Sherman: Richard Morton Sherman (born June 12, 1928) is an American songwriter who specialized in musical films with his brother Robert Bernard Sherman. According to the official Walt Disney Company website and independent fact checkers, "the Sherman Brothers were responsible for more motion picture musical song scores than any other songwriting team in film history." Some of the Sherman Brothers' best known songs were incorporated into live action and animation musical films including: "Mary Poppins", "The Jungle Book", "The Many Adventures of Winnie the Pooh", "Chitty Chitty Bang Bang", "Snoopy Come Home", "Bedknobs and Broomsticks", "The Slipper and the Rose", and "Charlotte's Web". Their most well known work, however, remains the theme park song "It's a Small World (After All)". According to Time.com, this song is the most performed song of all time.
Document 7: Winnie the Pooh (song): "Winnie the Pooh" is the title song for the franchise of the same name. It is musically emblematic of the most successful branding Disney currently owns and has been used in most merchandising models of the brand since the song's first publication in 1966 in the musical film featurette "Winnie the Pooh and the Honey Tree". In film, the song is generally utilized in the title sequence. The lyric gives an overview of the characters and the roles each plays in relation to Pooh himself. The song has been used in every theatrically released Pooh film as well as most of the television series. The songwriters are the Sherman Brothers, who have written the grand majority of Winnie the Pooh songs and musical numbers since 1966. It is unknown who performed the song. The song was also performed by Carly Simon. A music video was released for this version and it was included in "The Many Adventures of Winnie the Pooh" DVD.
Document 8: Carl Barks: Carl Barks (March 27, 1901 – August 25, 2000) was an American cartoonist, author, and painter. He is best known for his comics about Donald Duck and as the creator of Scrooge McDuck. He worked anonymously until late in his career; fans dubbed him The Duck Man and The Good Duck Artist. In 1987, Barks was one of the three inaugural inductees of the Will Eisner Comic Book Hall of Fame.
Document 9: Robert B. Sherman: Robert Bernard Sherman (December 19, 1925 – March 6, 2012) was an American songwriter who specialized in musical films with his brother Richard Morton Sherman. According to the official Walt Disney Company website and independent fact checkers, "the Sherman Brothers were responsible for more motion picture musical song scores than any other songwriting team in film history." Some of the Sherman Brothers' best known songs were incorporated into live action and animation musical films including: "Mary Poppins", "The Jungle Book", "The Many Adventures of Winnie the Pooh", "Chitty Chitty Bang Bang", "The Slipper and the Rose", and "Charlotte's Web". Their most well known work, however, remains the theme park song "It's a Small World (After All)". According to Time.com, this song is the most performed song of all time.
Document 10: Walt Disney's Comics and Stories: Walt Disney's Comics and Stories, sometimes abbreviated WDC or WDC&S, is an anthology comic book series that has an assortment of Disney characters, including Donald Duck, Scrooge McDuck, Mickey Mouse, Chip 'n Dale, Lil Bad Wolf, Scamp, Bucky Bug, Grandma Duck, Brer Rabbit, Winnie the Pooh, and others.
Document 11: Sherman Brothers: The Sherman Brothers were an American songwriting duo that specialized in musical films, made up of Robert B. Sherman (December 19, 1925 – March 6, 2012) and Richard M. Sherman (born June 12, 1928).
Document 12: Donald Duck: Donald Duck is a cartoon character created in 1934 at Walt Disney Productions. Donald is an anthropomorphic white duck with a yellow-orange bill, legs, and feet. He typically wears a sailor shirt and cap with a bow tie. Donald is most famous for his semi-intelligible speech and his mischievous and temperamental personality. Along with his friend Mickey Mouse, Donald is one of the most popular Disney characters and was included in TV Guide's list of the 50 greatest cartoon characters of all time in 2002. He has appeared in more films than any other Disney character, and is the most published comic book character in the world outside of the superhero genre.
Document 13: The Spectrum Song: "The Spectrum Song" was written by the Sherman Brothers in 1961 under assignment from Walt Disney to be a signature song for the fictional character Ludwig Von Drake. Nominally about different colors in the spectrum, the song's lyrics initially consist of the repeated color names red, yellow, green and blue, but soon veer wildly off into cerise, chartreuse, ultramarine and plaid.
Document 14: A Day in the Life of Donald Duck: "A Day in the Life of Donald Duck" is a 1956 episode of the "Disneyland" TV show. As the name of the episode implies, viewers experience Donald Duck himself as he struggles through a typical day at the Walt Disney Studios. In the process, he meets up with Jimmie Dodd, Roy Williams, the Mouseketeers and even his own voice, Clarence Nash. This episode introduces a song about Donald, "Quack, Quack, Quack, Donald Duck." This episode was released on DVD in 2006 as a bonus feature in the Walt Disney Treasures line.
Document 15: Ludwig Von Drake: Professor Ludwig Von Drake is one of Walt Disney's cartoon and comic book characters. He was first introduced on September 24, 1961, as the presenter (and singer of "The Spectrum Song") in the cartoon "An Adventure in Color", part of the first episode of "Walt Disney's Wonderful World of Color" on NBC. Said to be an uncle of Donald Duck. He is described as a scientist, lecturer, psychologist, and world traveler. The character displayed his "expert" knowledge on a variety of subjects in eighteen episodes of the classic anthology series, as well as on a number of Disneyland Records.
ground_truth: Donald Duck