Question: Riga International serves as a base airport for a Hungarian airline whose head office is in what city?
Context: Rumbula (ICAO: EVRC) is an air base located 11 km southeast of Riga city centre in Latvia.  The airfield had military use in the 1950s and 1960s.  In the 1960s it was used as temporary passenger airport for bigger planes until the new Riga International Airport was opened in 1973.  At least since 2001 there has been no military or commercial aviation based in Rumbula.  Now it is mainly used as the biggest auto market in Latvia, and only about five small general aviation planes are based here.  The runway is in very poor condition, with holes and concrete blocks often used to learn how to drive a car or for "test drives" of cars to be sold at the market.  It is difficult to find a continuous whole and obstacle-free piece of the runway which is more than 3000m long.  There are also a few "bomb-proof" camouflaged military hangars (one example is located at 56°53'08.39" N / 24°13'33.93" E).  The hangars are mainly used as storage or general purpose facilities; they are not obvious on satellite images and are not freely accessible on the ground. Sólyom Hungarian Airways Ltd. (] ) was a Hungarian airline start-up with its head office in Budapest at Budapest Liszt Ferenc International Airport It was founded in 2013 after Malév Hungarian Airlines, the former flag carrier of Hungary, ceased operations in February 2012.  It has never started operations. Air Kilroe Limited, trading as Eastern Airways, is a British airline whose head office is at Humberside Airport in Kirmington, North Lincolnshire, England.  It operates scheduled domestic and international services and private charter services.  Around 800,000 passengers a year are carried on the scheduled route network. Wizz Air, legally incorporated as "Wizz Air Hungary Ltd." (Hungarian: "Wizz Air Hungary Légiközlekedési Kft. " ), is a Hungarian low-cost airline with its head office in Budapest.  The airline serves many cities across Europe, Israel and the United Arab Emirates.  It has the largest fleet of any Hungarian airline, although it is not a flag carrier, and currently serves 42 countries.  Its Jersey based parent company, Wizz Air Holdings Plc, is listed on the London Stock Exchange and is a constituent of the FTSE 250 Index. Spilve Airport (Latvian: "Spilves lidosta" , also given as "Rīgas Centrālā Lidosta" – Riga Central Airport) is a former civilian and military airport in Latvia located 5 km north of Riga city centre, from which aircraft took off as early as the First World War.  It became the first international airport of Riga in the 1920s and fell into disuse in the 1980s after Riga International Airport was built. RAF-Avia is a Latvian airline headquartered in Riga and based at Riga International Airport. airBaltic, legally incorporated as AS Air Baltic Corporation, is a state-owned Latvian low-cost carrier and the country's flag carrier, with its head office on the grounds of Riga International Airport in Mārupe municipality near Riga.  Its main hub is at Riga International Airport with further bases at Tallinn Airport and Vilnius Airport. Concors Latvian Air Service was an airline based in Riga, Latvia.  Founded in 1991, it operated regional and international charter flights out of Riga International Airport between 1995 and 2005. Riga International Airport (Latvian: "Starptautiskā lidosta "Rīga"" ; IATA: RIX, ICAO: EVRA ) is the international airport of Riga, the capital of Latvia, and the largest airport in the Baltic states with direct flights to over 90 destinations in 30 countries.  It serves as a hub for airBaltic, SmartLynx Airlines, RAF-Avia, Vip Avia and Inversija and as one of the base airports for Wizz Air.  Latvian national carrier airBaltic is the biggest in the airport, followed by Ryanair. Inversija was a cargo airline based in Riga, Latvia.  It started operations in March 1991 and undertakes all types of cargo operations, as well as maintenance work for third parties.  Its main base was Riga International Airport.
Answer: Budapest