Question: The Russian composer of an 1893 symphony in E flat major had a student during the early Soviet years, what was the best known student's name?

Context paragraphs:
String Quartet No. 16 (Mozart): The String Quartet No. 16 in E flat major, K.  428/421b, was composed by Wolfgang Amadeus Mozart.  This is the third of the Haydn Quartets, a set of six string quartets he wrote during his first few years in Vienna and later dedicated to Joseph Haydn.

Serenade in E-flat major (Saint-Saëns): Camille Saint-Saëns' Serenade in E flat major, Op. 15 (French: "Sérénade en mi bémol majeur" ) is a chamber composition for a quartet consisting of piano, organ, violin, viola (or cello) composed in 1865.  It is one of the earliest works by the composer making use of an organ (or harmonium) in a chamber ensemble, preceded only by the Six Duos for harmonium and piano, Op. 8.  In addition to the original scoring the work has been transcribed for orchestra, piano solo, piano four-hands and for piano quartet, with a cello taking the part of the organ.

Lenny (instrumental): "Lenny" is the tenth and final track on the first Stevie Ray Vaughan album "Texas Flood".  The song is in 4/4 time and notated in the key of E flat major (but instruments are tuned down a half-step).  It is played very slowly and freely, with Vaughan alternating between jazz-inflected chords and solo runs.  The main chord featured in the song is a movable Major 6th chord in which Stevie Ray Vaughan applies moderate vibrato by use of tremolo bar.  The solos incorporate both the E major scale, E minor Pentatonic scale, and E Minor Blues scale.  The style is influenced by Jimi Hendrix ballads like "Little Wing" and "Angel".  The song itself was written and named for his wife at the time, Lenora.  Vaughan also named one of his guitars "Lenny", which he used to play this song and also "Riviera Paradise".  The song was often played at live shows.

Rustic Wedding Symphony: Rustic Wedding Symphony, Op. 26 ("Ländliche Hochzeit") is a symphony in E flat major by Karl Goldmark, written in 1875, a year before his renowned Violin Concerto No. 1.

String Quartet No. 3 (Nielsen): Carl Nielsen's String Quartet No. 3 in E flat major or Quartet for Two Violins, Viola and Cello in E flat major, Opus 14, was composed in 1897 and 1898.  The third of Nielsen's four string quartets in the official series, it was first performed privately in "Vor Forening" (Our Society) on 1 May 1899 with Anton Svendsen, Ludvig Holm, Frederik Marke and Ejler Jensen as performers.

Symphony No. 4 (Glazunov): The Symphony No. 4 in E flat major, Op.  48, was written by Alexander Glazunov in 1893.  The symphony was a departure from Glazunov's three earlier symphonies, which were based on nationalistic Russian tunes and, according to the composer, allowed him to give "personal, free, and subjective impressions of myself."

Piano Sonata No. 2 (Kabalevsky): Dmitry Kabalevsky's Piano Sonata No. 2 in E flat major, Op. 45 was composed in 1945 and dedicated to Emil Gilels.  It is the most vast and dramatic of Kabalevsky's three sonatas.  A War Sonata such as Sergei Prokofiev's trilogy, its first movement has been compared to that of Dmitri Shostakovich's Symphony No. 7.

Symphony No. 3 (Shostakovich): The Symphony No. 3 in E flat major (Opus 20; subtitled "First of May") by Dmitri Shostakovich was first performed by the Leningrad Philharmonic Orchestra and Academy Capella Choir under Aleksandr Gauk on 21 January 1930 (the anniversary of Lenin's death).

Symphony No. 19 (Mozart): Symphony No. 19 in E flat major, K. 132, is a symphony composed by Wolfgang Amadeus Mozart in July, 1772.

Alexander Glazunov: Alexander Konstantinovich Glazunov (Russian: Алекса́ндр Константи́нович Глазуно́в , 10 August 1865 – 21 March 1936) was a Russian composer, music teacher, and conductor of the late Russian Romantic period.  He served as director of the Saint Petersburg Conservatory between 1905 and 1928 and was instrumental in the reorganization of the institute into the Petrograd Conservatory, then the Leningrad Conservatory, following the Bolshevik Revolution.  He continued heading the Conservatory until 1930, though he had left the Soviet Union in 1928 and did not return.  The best-known student under his tenure during the early Soviet years was Dmitri Shostakovich.

Supporting paragraphs: Symphony No. 4 (Glazunov) Alexander Glazunov
Answer: Dmitri Shostakovich