Question: Which opera has more acts, Riders to the Sea or Lucio Silla?
Context: The Symphony in D major, K. 135+61h, was probably composed by Wolfgang Amadeus Mozart in 1772.  All the movements are from the overture to the opera "Lucio Silla", K. 135, except for the minuet, K. 61h No. 3, which was composed separately. The six string quartets, K. 155–160, were composed by Wolfgang Amadeus Mozart in late 1772 and early 1773.  Because they were composed in Milan while he was working on his opera Lucio Silla, they are popularly known as the Milanese Quartets.  Before this set was composed, Mozart had written one earlier string quartet (K. 80/73f in 1770), so these six quartets are ordinally numbered from No. 2 to No. 7.  The quartets are written in a plan of keys of D-G-C-F-B♭ -E♭ following the circle of fifths. Jang Bogo (787–846), childhood name: Gungbok, was a Sillan who rose to prominence in the Later Silla period of Korea as a powerful maritime figure who effectively controlled the Yellow Sea (West Sea), and dominated the trade between Silla, Heian Japan, and Tang China for decades.  His impressive fleet of ships was centered in Wando, an island in South Jeolla Province.  So influential a figure did Jang become in late Silla politics that he was granted official office as Maritime Commissioner of the Cheonghaejin Garrison (on Wando) and came near to marrying his daughter into the Silla Royal House before his assassination in 846.  He was worshipped as a god following his death. The Teatro Regio Ducal (Italian, "Royal Ducal Theatre") was the opera house in Milan from 26 December 1717 until 25 February 1776, when it was burned down following a carnival gala.  Many famous composers and their operas are associated with it, including the premieres of Mozart's "Ascanio in Alba", "Mitridate, re di Ponto", and "Lucio Silla".  The opera house also saw the premiere of Maria Teresa Agnesi Pinottini's "Ciro in Armenia" in 1753; one of the earliest successfully received operas by a female composer.  Variant forms such as "Regio-Ducal Teatro" and "Teatro Regio Ducale" are also seen. Riders to the Sea is a short one-act opera by Ralph Vaughan Williams, based on the play of the same name by John Millington Synge.  The composer completed the score in 1927, but it was not premiered until 1 December 1937, at the Royal College of Music, London.  The opera remained largely the province of students and amateurs until it entered the repertoire of Sadler's Wells in 1953. Silla (full title "Lucio Cornelio Silla", HWV 10) is an opera seria (referred to as a "dramma per musica") in three acts by George Frideric Handel.  The Italian-language libretto was by Giacomo Rossi.  The story concerns the Roman dictator Lucius Cornelius Sulla (138–78 BC) as recounted by Plutarch. Lucio Silla (pronounced , ] ), K. 135, is an Italian opera in three acts composed by Wolfgang Amadeus Mozart.  The libretto was written by Giovanni de Gamerra. The Symphony No. 25 in G minor, K.  183/173dB, was written by the then 17-year-old Wolfgang Amadeus Mozart in October 1773, shortly after the success of his opera seria "Lucio Silla".  It was supposedly completed in Salzburg on October 5, a mere two days after the completion of his Symphony No. 24, although this remains unsubstantiated.  Its first movement is widely known as the opening music in Miloš Forman's film "Amadeus". Korea's military history spans thousands of years, beginning with the ancient nation of Gojoseon and continuing into the present day with the countries of North Korea and South Korea, and is notable for its many successful triumphs over invaders.  Throughout its history, Korea has boasted numerous exceptional leaders who gained outstanding victories against numerically superior enemies.  Famed leaders credited with defending Korea against foreign invasions include: Eulji Mundeok of Goguryeo, who defeated Sui China during the Goguryeo–Sui War; Yeon Gaesomun of Goguryeo, who defeated Emperor Taizong of Tang China during the Goguryeo–Tang War; Gang Gam-chan of Goryeo, who defeated the Khitan Empire during the Goryeo-Khitan War; Choe Yeong and Yi Seong-gye of Goryeo, who defeated the Red Turbans, who later established Ming China, during the Red Turban Invasions; and Yi Sun-shin of Joseon, who defeated the Japanese at sea during the Imjin War.  Other notable leaders include: Gwanggaeto the Great of Goguryeo, who created a great empire in Northeast Asia through conquest, and subjugated the other Korean kingdoms of Baekje, Silla and Gaya to bring about a brief unification of the Three Kingdoms of Korea; Geunchogo of Baekje, who captured Pyongyang and established overseas territories to control much of the Korean peninsula and dominate the seas; Munmu and Kim Yu-sin of Silla, who united the Three Kingdoms of Korea and defeated Tang China to gain complete control of the Korean peninsula; Dae Jo-yeong, who created Balhae from Goguryeo's ashes and reconquered Goguryeo lands lost during the Goguryeo-Tang War; Jang Bogo of Later Silla, who created a maritime empire and commanded a powerful fleet; Wang Geon, who united the Later Three Kingdoms of Korea and established Goryeo as the successor to Goguryeo; and Yun Gwan of Goryeo, who defeated the Jurchens and constructed nine fortresses in Manchuria. Anna Lucia de Amicis (c. 1733–1816) was an Italian soprano.  She debuted in J. C. Bach's "Orione" in London, and went on to sing as prima donna in Dublin, Innsbruck and Naples.  In Innsbruck she sang the female title role in "Romolo ed Ersilia", the marriage celebration opera written by Johann Adolf Hasse for the marriage of Leopold of Habsburg and Spanish Infanta Maria Ludovica.  For this role she gained a lot of reputation.  She was a favourite of both Mozart and his father Leopold, and created the role of Giunia in "Lucio Silla" (Milan 1772).
Answer: Lucio Silla