Question: The Dream Chord is a chord, it is made up of which pitches, that is used prominently in the works of La Monte Young, an American avant-garde composer, musician, and artist generally recognized as the first minimalist composer?
Context: Sonatas and Interludes is a collection of twenty pieces for prepared piano by American avant-garde composer John Cage (1912–1992).  It was composed in 1946–48, shortly after Cage's introduction to Indian philosophy and the teachings of art historian Ananda K. Coomaraswamy, both of which became major influences on the composer's later work.  Significantly more complex than his other works for prepared piano, "Sonatas and Interludes" is generally recognized as one of Cage's finest achievements. The Theatre of Eternal Music, sometimes later known as The Dream Syndicate, was a mid-1960s musical group formed by La Monte Young, that focused on experimental drone music.  It featured the performances of La Monte Young, John Cale, Angus MacLise, Terry Jennings, Marian Zazeela, Tony Conrad, Billy Name, Jon Hassell, Alex Dea and others.  The group is stylistically tied to the Neo-Dada aesthetics of Fluxus and the post-John Cage noise music continuum. La Monte Thornton Young (born October 14, 1935) is an American avant-garde composer, musician, and artist generally recognized as the first minimalist composer.  His works are cited as notable examples of post-war experimental and contemporary music, and were tied to New York's downtown music and Fluxus art scenes. The Magic Chord is a chord and installation (1984) created by La Monte Young, consisting of the pitches E, F, A, B♭ , D, E, G, and A, in ascending order and used in works including his "The Well-Tuned Piano" and "Chronos Kristalla" (1990).  The latter was performed by the Kronos Quartet and features all notes of the magic chord as harmonics on open strings.  The quartet has been described as, "offer[ing] perhaps the ultimate challenge in performing in a just environment." Anthony Schmalz "Tony" Conrad (March 7, 1940 – April 9, 2016) was an American avant-garde video artist, experimental filmmaker, musician, composer, sound artist, teacher, and writer.  Active in a variety of media since the early 1960s, he was a pioneer of both structural film and drone music.  He performed and collaborated with a wide range of artists over the course of his career, most prominently La Monte Young's 1960s New York experimental music group Theatre of Eternal Music. Marian Zazeela (born April 15, 1940) is a light-artist, designer, painter and musician based in New York City.  She was a member of the 1960s New York experimental music collective Theatre of Eternal Music, and is known for her collaborative work with minimalist composer La Monte Young. The Dream Chord is a chord that is used prominently in the works of La Monte Young.  It is made up of the pitches G-C-C sharp-D.  The chord is prominently featured in Young's compositions ""for Brass"", ""Trio"", and ""The Four Dreams of China"". Idaho has produced a number of musicians and bands, including Paul Revere & the Raiders (who had a #1 Billboard Hot 100 hit with "Indian Reservation (The Lament of the Cherokee Reservation Indian)" in 1971) and Doug Martsch of Built to Spill.  Rosalie Sorrels is a renowned folk singer born in Boise.  Minimalist composer La Monte Young was born in Bern.  Jazz double bassist Gary Peacock was born in Burley.  Nikki Sixx (bassist of glam metal band Mötley Crüe) grew up in Jerome.  Moscow, Idaho is the home town of modern folk/country/indie songwriter Josh Ritter. In C is a musical piece composed by Terry Riley in 1964 for an indefinite number of performers.  He suggests "a group of about 35 is desired if possible but smaller or larger groups will work".  A series of short melodic fragments, "In C" is a response to the abstract academic serialist techniques devised by Schoenberg that dominated Western university composers for many decades and is often cited as the first minimalist composition (though La Monte Young's drone compositions preceded it by several years, "In C" had a greater impact on public consciousness). Originally released by the French label Shandar with the catalog number Shandar 83.510 and never re-released on CD, Dream House 78' 17" is one of the very few recordings ever made by minimalist composer La Monte Young, in this case together with his long-time companion Marian Zazeela and his group the Theatre of Eternal Music.  The 78' 17" in the title consists of the duration of the record measured in minutes and seconds.  This length, almost double what was then normal, was extremely unusual in its time.  Young in the sleeve notes says that "Time is so important to the experiencing and understanding of the music in the record that every effort was made to make the record last as much as the original master tapes".  Young thanks Mr. Michel Blancvillain who made it technically possible.
Answer: G-C-C sharp-D