Question: The husband of Verna Avey composed how many symphonies?

full_context: Document 1: A Bayou Legend: A Bayou Legend is an American opera composed by William Grant Still, with a libretto by his wife and frequent collaborator, Verna Arvey.
Document 2: Verna Arvey: Verna Arvey (February 16, 1910 – November 22, 1987) was an American librettist, pianist and writer who is best known for her musical collaborations with her husband William Grant Still, a musician and composer.
Document 3: Stephen Paulus: Stephen Paulus (August 24, 1949 – October 19, 2014) was a Grammy winning American composer, best known for his operas and choral music. His best-known piece is his 1982 opera "The Postman Always Rings Twice", one of several operas he composed for the Opera Theatre of St. Louis, which prompted "The New York Times" to call him "a young man on the road to big things". His style is essentially tonal, and melodic and romantic by nature. He received grants from the National Endowment for the Arts and Guggenheim Foundation and won the prestigious Kennedy Center Friedheim Prize. He was commissioned by such notable organizations as the Minnesota Opera, the Chamber Music Society of Lincoln Center, Opera Theatre of Saint Louis, the Saint Louis Chamber Chorus, the American Composers Orchestra, the Dale Warland Singers, the Harvard Glee Club and the New York Choral Society. Paulus was a passionate advocate for the works and careers of his colleagues. He co-founded the American Composers Forum in 1973, the largest composer service organization in the U.S., and served as the Symphony and Concert Representative on the ASCAP Board of Directors from 1990 until his death (from complications following a stroke in July 2013) in 2014.
Document 4: Mississippi Opera: The Mississippi Opera is an American opera company located in Jackson, Mississippi. Founded in 1945, the company presents an annual season of opera consisting of two fully staged opera productions and smaller concerts and workshops open to the public. The company's productions are performed at the Belhaven University Center for the Arts. Composer William Grant Still and soprano Leontyne Price both have associations with the company.
Document 5: Frederick Douglass (Ulysses Kay opera): Frederick Douglass is an opera in three acts composed by Ulysses Kay to a libretto by Donald Dorr. Its story is a semi-fictionalized account of the final years in the life of Frederick Douglass after his marriage to his second wife, Helen Pitts Douglass. The opera premiered on April 12, 1991 at Newark Symphony Hall performed by the New Jersey State Opera in a production directed by Louis Johnson and designed by Salvatore Tagliarino.
Document 6: George Gershwin: George Jacob Gershwin ( ; September 26, 1898 July 11, 1937) was an American composer and pianist. Gershwin's compositions spanned both popular and classical genres, and his most popular melodies are widely known. Among his best-known works are the orchestral compositions "Rhapsody in Blue" (1924) and "An American in Paris" (1928) as well as the opera "Porgy and Bess" (1935).
Document 7: Still Waters Youth Sinfo-Nia: Still Waters Sinfo-Nia is a predominantly African-American youth orchestra located in Atlanta, Georgia, United States. It was originally called the William Grant Still Memorial Orchestra. The organization was started in 1990 and has been led by David E. Robinson III.
Document 8: Troubled Island: Troubled Island is an American opera in three acts composed by William Grant Still, with a libretto begun by poet Langston Hughes and completed by Verna Arvey. She married the composer following their collaboration.
Document 9: Will Vodery: Will Vodery (October 8, 1885 - November 18, 1951) was an African-American composer, conductor, orchestrator, and arranger, and one of the few black Americans of his time to make a name for himself as a composer on Broadway, working largely for Florenz Ziegfeld.
Document 10: Four Last Songs (Vaughan Williams): Ralph Vaughan Williams' Four Last Songs cycle is made up of four songs: "Procris," "Tired," "Hands, Eyes, and Heart," and "Menelaus." All of the songs were composed between 1954 and 1958. The cycle is best suited for mezzo-soprano, although, the original program note from the cycle's 1959 premiere acknowledges that all of the songs may be sung by a baritone, except for "Hands, Eyes, and Heart" "which is a woman's song." It is suggested that the four songs were originally intended to be two separate song cycles with "Menelaus" and "Procris" belonging to one cycle and "Tired" and "Hands, Eyes, and Heart" belonging to another. However, there is debate in the scholarly community about this proposed song cycle grouping. Renée Chérie Clark in her essay, "A Critical Appraisal of Four Last Songs" suggests, citing a letter from the composer to a friend at Cornell University, that Vaughan Williams actually intended for "Menelaus" and "Hands, Eyes, and Heart" to be grouped together. The composer's death in 1958 left both cycles unfinished, and in 1960, they were assembled by the composer's widow, Ursula Vaughan Williams, and published as set by Oxford University Press. The texts of all four songs are poems written by Vaughan Williams' wife Ursula who penned several books of poetry throughout her lifetime as well as a biography of her late husband. "Procris" and "Menelaus" deal with figures from ancient Greek and Roman mythology and epic poetry while "Tired" and "Hands, Eyes, and Heart" depict images of love between a husband and wife.
Document 11: List of compositions by Franz Schubert by genre: Franz Schubert (31 January 1797 – 19 November 1828) was an extremely prolific Austrian composer. He composed some 1500 works (or, when collections, cycles and variants are grouped, some thousand compositions). The largest group are the lieder for piano and solo voice (over six hundred), and nearly as many piano pieces. Schubert also composed some 150 part songs, some 40 liturgical compositions (including several masses) and around 20 stage works like operas and incidental music. His orchestral output includes a dozen symphonies (seven completed) and several overtures. Schubert's chamber music includes over 20 string quartets, and several quintets, trios and duos.
Document 12: I Got Plenty o' Nuttin': "I Got Plenty o' Nuttin'" is a song composed in 1934 by George Gershwin for the 1935 "folk-opera" "Porgy and Bess" (1934). The lyrics are by DuBose Heyward, the author of the novel "Porgy" on which the opera was based, and Ira Gershwin. It is one of the most famous songs from the opera (along with "Summertime," "It Ain't Necessarily So", and "Bess, You Is My Woman Now") and it has been recorded by hundreds of singers and music groups.
Document 13: C. William Harwood: C. William Harwood (March 14, 1948, Richmond, Virginia - April 26, 1984, Little Rock, Arkansas) was an American conductor. Chiefly remembered for his work as an opera conductor, he notably conducted the Houston Grand Opera's groundbreaking 1977 national tour of George Gershwin's "Porgy and Bess". He also conducted the world premieres of operas by Claude Debussy, Frederick Delius, Stephen Paulus, and George Rochberg.
Document 14: Symphony No. 1 &quot;Afro-American&quot;: Symphony No. 1 in A-flat, "Afro-American" (1930) by William Grant Still was the first symphony written by an African American and performed for a United States audience by a leading orchestra. It was premiered in 1931 by the Rochester Philharmonic Orchestra. It is a symphonic piece for full orchestra, including celeste, harp, and tenor banjo. It combines a fairly traditional symphonic form with blues progressions and rhythms that were characteristic of popular African-American music at the time. This combination expressed Still's integration of black culture into the classical forms. Still used quotes from four dialect poems by early 20th-century African-American poet Paul Laurence Dunbar as epigraphs for each symphonic movement.
Document 15: William Grant Still: William Grant Still (May 11, 1895 – December 3, 1978) was an American composer, who composed more than 150 works, including five symphonies and eight operas.
ground_truth: five