Question: What instrument did the guitarist for the band Cream study?

full_context: Document 1: Hard rock: In the early 1970s the Rolling Stones developed their hard rock sound with Exile on Main St. (1972). Initially receiving mixed reviews, according to critic Steve Erlewine it is now "generally regarded as the Rolling Stones' finest album". They continued to pursue the riff-heavy sound on albums including It's Only Rock 'n' Roll (1974) and Black and Blue (1976). Led Zeppelin began to mix elements of world and folk music into their hard rock from Led Zeppelin III (1970) and Led Zeppelin IV (1971). The latter included the track "Stairway to Heaven", which would become the most played song in the history of album-oriented radio. Deep Purple continued to define hard rock, particularly with their album Machine Head (1972), which included the tracks "Highway Star" and "Smoke on the Water". In 1975 guitarist Ritchie Blackmore left, going on to form Rainbow and after the break-up of the band the next year, vocalist David Coverdale formed Whitesnake. 1970 saw The Who release Live at Leeds, often seen as the archetypal hard rock live album, and the following year they released their highly acclaimed album Who's Next, which mixed heavy rock with extensive use of synthesizers. Subsequent albums, including Quadrophenia (1973), built on this sound before Who Are You (1978), their last album before the death of pioneering rock drummer Keith Moon later that year.
Document 2: Hard rock: The roots of hard rock can be traced back to the 1950s, particularly electric blues, which laid the foundations for key elements such as a rough declamatory vocal style, heavy guitar riffs, string-bending blues-scale guitar solos, strong beat, thick riff-laden texture, and posturing performances. Electric blues guitarists began experimenting with hard rock elements such as driving rhythms, distorted guitar solos and power chords in the 1950s, evident in the work of Memphis blues guitarists such as Joe Hill Louis, Willie Johnson, and particularly Pat Hare, who captured a "grittier, nastier, more ferocious electric guitar sound" on records such as James Cotton's "Cotton Crop Blues" (1954). Other antecedents include Link Wray's instrumental "Rumble" in 1958, and the surf rock instrumentals of Dick Dale, such as "Let's Go Trippin'" (1961) and "Misirlou" (1962).
Document 3: London: London has numerous venues for rock and pop concerts, including the world's busiest arena the o2 arena and other large arenas such as Earls Court, Wembley Arena, as well as many mid-sized venues, such as Brixton Academy, the Hammersmith Apollo and the Shepherd's Bush Empire. Several music festivals, including the Wireless Festival, South West Four, Lovebox, and Hyde Park's British Summer Time are all held in London. The city is home to the first and original Hard Rock Cafe and the Abbey Road Studios where The Beatles recorded many of their hits. In the 1960s, 1970s and 1980s, musicians and groups like Elton John, Pink Floyd, David Bowie, Queen, The Kinks, The Rolling Stones, The Who, Eric Clapton, Led Zeppelin, The Small Faces, Iron Maiden, Fleetwood Mac, Elvis Costello, Cat Stevens, The Police, The Cure, Madness, The Jam, Dusty Springfield, Phil Collins, Rod Stewart and Sade, derived their sound from the streets and rhythms vibrating through London.
Document 4: Marshall Bluesbreaker: The Bluesbreaker, which derives its nickname from being used by Eric Clapton with John Mayall & The Bluesbreakers, is credited with delivering "the sound that launched British blues-rock in the mid-1960s." It was Marshall's first combo amplifier, and was described as "arguably the most important [amplifier] in the company's history" and "the definitive rock amplifier."
Document 5: The Beatles: The Beatles were an English rock band formed in Liverpool in 1960. With members John Lennon, Paul McCartney, George Harrison and Ringo Starr, they became widely regarded as the foremost and most influential act of the rock era. Rooted in skiffle, beat and 1950s rock and roll, the Beatles later experimented with several musical styles, ranging from pop ballads and Indian music to psychedelia and hard rock, often incorporating classical elements and unconventional recording techniques in innovative ways. In 1963 their enormous popularity first emerged as ``Beatlemania ''; as the group's music grew in sophistication, led by primary songwriters Lennon and McCartney, the band were integral to pop music's development into an art form and came to be perceived as an embodiment of the ideals shared by the counterculture of the 1960s.
Document 6: Hard rock: Groups that emerged from the American psychedelic scene about the same time included Iron Butterfly, MC5, Blue Cheer and Vanilla Fudge. San Francisco band Blue Cheer released a crude and distorted cover of Eddie Cochran's classic "Summertime Blues", from their 1968 debut album Vincebus Eruptum, that outlined much of the later hard rock and heavy metal sound. The same month, Steppenwolf released its self-titled debut album, including "Born to Be Wild", which contained the first lyrical reference to heavy metal and helped popularise the style when it was used in the film Easy Rider (1969). Iron Butterfly's In-A-Gadda-Da-Vida (1968), with its 17-minute-long title track, using organs and with a lengthy drum solo, also prefigured later elements of the sound.
Document 7: London: London was instrumental in the development of punk music, with figures such as the Sex Pistols, The Clash, and Vivienne Westwood all based in the city. More recent artists to emerge from the London music scene include George Michael, Kate Bush, Seal, Siouxsie and the Banshees, Bush, the Spice Girls, Jamiroquai, Blur, The Prodigy, Gorillaz, Mumford & Sons, Coldplay, Amy Winehouse, Adele, Ed Sheeran and One Direction. London is also a centre for urban music. In particular the genres UK garage, drum and bass, dubstep and grime evolved in the city from the foreign genres of hip hop and reggae, alongside local drum and bass. Black music station BBC Radio 1Xtra was set up to support the rise of home-grown urban music both in London and in the rest of the UK.
Document 8: Bruce Molsky: As a young man, Molsky first became interested in blues music, but eventually became absorbed in old-time music while studying engineering at Cornell University in Ithaca, New York, beginning in 1972. His playing was influenced by the fiddling of Tommy Jarrell, whom Molsky visited in North Carolina in 1976. He recorded with Bob Carlin in 1990.
Document 9: Mandolin: Mandolin has also been used in blues music, most notably by Ry Cooder, who performed outstanding covers on his very first recordings, Yank Rachell, Johnny "Man" Young, Carl Martin, and Gerry Hundt. Howard Armstrong, who is famous for blues violin, got his start with his father's mandolin and played in string bands similar to the other Tennessee string bands he came into contact with, with band makeup including "mandolins and fiddles and guitars and banjos. And once in a while they would ease a little ukulele in there and a bass fiddle." Other blues players from the era's string bands include Willie Black (Whistler And His Jug Band), Dink Brister, Jim Hill, Charles Johnson, Coley Jones (Dallas String Band), Bobby Leecan (Need More Band), Alfred Martin, Charlie McCoy (1909-1950), Al Miller, Matthew Prater, and Herb Quinn.
Document 10: Hard rock: In the 1960s, American and British blues and rock bands began to modify rock and roll by adding harder sounds, heavier guitar riffs, bombastic drumming, and louder vocals, from electric blues. Early forms of hard rock can be heard in the work of Chicago blues musicians Elmore James, Muddy Waters, and Howlin' Wolf, The Kingsmen's version of "Louie Louie" (1963) which made it a garage rock standard, and the songs of rhythm and blues influenced British Invasion acts, including "You Really Got Me" by The Kinks (1964), "My Generation" by The Who (1965), "Shapes of Things" (1966) by The Yardbirds and "(I Can't Get No) Satisfaction" (1965) by The Rolling Stones. From the late 1960s, it became common to divide mainstream rock music that emerged from psychedelia into soft and hard rock. Soft rock was often derived from folk rock, using acoustic instruments and putting more emphasis on melody and harmonies. In contrast, hard rock was most often derived from blues rock and was played louder and with more intensity.
Document 11: Eric Clapton: Clapton was born on 30 March 1945 in Ripley, Surrey, England, to 16-year-old Patricia Molly Clapton (7 January 1929 – March 1999) and Edward Walter Fryer (21 March 1920 – 15 May 1985), a 25-year-old soldier from Montreal, Quebec. Fryer shipped off to war prior to Clapton's birth and then returned to Canada. Clapton grew up believing that his grandmother, Rose, and her second husband, Jack Clapp, Patricia's stepfather, were his parents, and that his mother was actually his older sister. The similarity in surnames gave rise to the erroneous belief that Clapton's real surname is Clapp (Reginald Cecil Clapton was the name of Rose's first husband, Eric Clapton's maternal grandfather). Years later, his mother married another Canadian soldier and moved to Germany, leaving young Eric with his grandparents in Surrey.Clapton received an acoustic Hoyer guitar, made in Germany, for his thirteenth birthday, but the inexpensive steel-stringed instrument was difficult to play and he briefly lost interest. Two years later Clapton picked it up again and started playing consistently. Clapton was influenced by the blues from an early age, and practised long hours to learn the chords of blues music by playing along to the records. He preserved his practice sessions using his portable Grundig reel-to-reel tape recorder, listening to them over and over until he felt he'd got it right.In 1961, after leaving Hollyfield School in Surbiton, Clapton studied at the Kingston College of Art but was dismissed at the end of the academic year because his focus remained on music rather than art. His guitar playing was so advanced that, by the age of 16, he was getting noticed. Around this time, Clapton began busking around Kingston, Richmond, and the West End.
Document 12: Hard rock: Blues rock acts that pioneered the sound included Cream, The Jimi Hendrix Experience, and The Jeff Beck Group. Cream, in songs like "I Feel Free" (1966) combined blues rock with pop and psychedelia, particularly in the riffs and guitar solos of Eric Clapton. Jimi Hendrix produced a form of blues-influenced psychedelic rock, which combined elements of jazz, blues and rock and roll. From 1967 Jeff Beck brought lead guitar to new heights of technical virtuosity and moved blues rock in the direction of heavy rock with his band, The Jeff Beck Group. Dave Davies of The Kinks, Keith Richards of The Rolling Stones, Pete Townshend of The Who, Hendrix, Clapton and Beck all pioneered the use of new guitar effects like phasing, feedback and distortion. The Beatles began producing songs in the new hard rock style beginning with the White Album in 1968 and, with the track "Helter Skelter", attempted to create a greater level of noise than the Who. Stephen Thomas Erlewine of AllMusic has described the "proto-metal roar" of "Helter Skelter," while Ian MacDonald argued that "their attempts at emulating the heavy style were without exception embarrassing."
Document 13: Robin Blaze: The son of Peter, a professional golfer, and Christine, Robin Blaze, with his brother Mark, grew up in Shadwell, near Leeds, and was educated at Leeds Grammar School, Uppingham School, and Magdalen College, Oxford. Having made his first solo recordings as a treble with Stephen Lomas, Blaze was both a chorister and an academical clerk at Magdalen College where he recorded with the Dufay Consort. After graduating, he won a scholarship for postgraduate studies at the Royal College of Music, where he continued to study with Michael Chance and Ashley Stafford. After completing his education, he took a position as professor of Vocal Studies at the Royal College. He has also studied flute, piano, and organ.
Document 14: Steve Smith (American Dad!): A freshman at Pearl Bailey High School, Steve is a highly capable musician, having taken up the cello to once impress a girl. In a later episode, however, Steve says that he has been playing the cello since he was nine. Steve also plays guitar and sings, which he did as part of a band in the episode ``American Dream Factory. ''In fact, both of the songs Steve's band rehearses (`` Livin 'on the Run'' and ``Sunset Blvd ''), were originally recorded by Scott Grimes, who voices Steve. Among Steve's other talents are being able to read Elvish, use Morse code, and communicate with dolphins.
Document 15: Stevie Blacke: Born in London and raised in Ohio, Blacke grew up with the music of Eric Clapton and Pink Floyd, before he attended the Berklee College of Music to study guitar, mandolin and violin. He learned and first recorded cello during a session for a hip hop artist.
ground_truth: violin
sub_queries: Who was the guitarist for the band Cream? Answer: Eric Clapton
Eric Clapton >> instrument Answer: violin