Question: The composer of the opera "The Zoo" has composed how many major orchestral works?

Related documents: [0]  [DOC] Sir Arthur Seymour Sullivan MVO (13 May 1842 – 22 November 1900) was an English composer. He is best known for his series of 14 operatic collaborations with the dramatist W. S. Gilbert, including "H.M.S. Pinafore", "The Pirates of Penzance" and "The Mikado". His works include 23 operas, 13 major orchestral works, eight choral works and oratorios, two ballets, incidental music to several plays, and numerous hymns and other church pieces, songs, and piano and chamber pieces. The best known of his hymns and songs include "Onward Christian Soldiers" and "The Lost Chord". [END] 
[1]  [DOC] The Zoo is a one-act comic opera, with music by Arthur Sullivan and a libretto by B. C. Stephenson, writing under the pen name of Bolton Rowe. It premiered on 5 June 1875 at the St. James's Theatre in London (as an afterpiece to W. S. Gilbert's "Tom Cobb"), concluding its run five weeks later, on 9 July 1875, at the Haymarket Theatre. There were brief revivals in late 1875, and again in 1879, before the opera was shelved. [END]  
Answer: 13
13