In this task, you are given a context, a subject, a relation, and many options. Based on the context, from the options select the object entity that has the given relation with the subject. Answer with text (not indexes).

Context: Sadiq Aman Khan (born 8 October 1970) is a British politician and the current Mayor of London since May 2016. He was the Member of Parliament (MP) for Tooting from 2005 to 2016. A member of the Labour Party, he is situated on the party's soft left and has been ideologically characterised as a social democrat., The 2004 election to the post of Mayor of London took place on 10 June 2004 . It was held on the same day as other local elections and the UK part of the 2004 European Parliament elections . The election was won by incumbent mayor , Ken Livingston , who stood as a candidate for the Labour Party and once again soundly defeated Steven Norris , the Conservative Party candidate ., Kenneth Robert "Ken" Livingstone (born 17 June 1945) is an English politician who served as the Leader of the Greater London Council (GLC) from 1981 until the council was abolished in 1986, and as Mayor of London from the creation of the office in 2000 until 2008. He also served as the Member of Parliament (MP) for Brent East from 1987 to 2001. A suspended member of the Labour Party, he was on the party's hard left, ideologically identifying as a democratic socialist., Alexander Boris de Pfeffel Johnson (born 19 June 1964), known as Boris Johnson, is a British politician, popular historian, author, and journalist. He has been UK Secretary of State for Foreign and Commonwealth Affairs since July 2016 and a Member of Parliament (MP) for the Uxbridge and South Ruislip constituency since May 2015. He had previously been an MP for the Henley constituency from 2001 to 2008 and was later Mayor of London from 2008 to 2016. A member of the Conservative Party, Johnson identifies as a "one-nation conservative" and has been associated with both economically and socially liberal policies.
Born in New York City to wealthy upper-middle class English parents, Johnson was educated at the European School of Brussels, Ashdown House School, and Eton College. He studied Classics at Balliol College, Oxford, where he was elected president of the Oxford Union in 1986. Beginning his career in journalism at "The Times" before being sacked for inventing a quote, he later became "The Daily Telegraph"s Brussels correspondent, with his articles exerting a strong influence on growing Eurosceptic sentiment among the British right-wing. He was assistant editor from 1994 to 1999 before taking the editorship of "The Spectator" from 1999 to 2005. Joining the Conservatives, he was elected MP for Henley in 2001, and under Michael Howard and David Cameron he was in the Shadow Cabinet. Mostly adhering to the Conservatives' party line, he nevertheless adopted a more socially liberal stance on issues like LGBT rights in parliamentary votes. Making regular television appearances, writing books, and remaining active in journalism, Johnson became one of the most conspicuous politicians in Britain.
Selected as Conservative candidate for the London mayoral election of 2008, Johnson defeated Labour incumbent Ken Livingstone and resigned his seat in parliament. During his first term as mayor, he banned alcohol consumption on public transport, championed London's financial sector, and introduced the New Routemaster buses, cycle hire scheme, and Thames cable-car. In 2012, he was re-elected mayor, again defeating Livingstone; during his second term he oversaw the 2012 Summer Olympics. In 2015 he was elected MP for Uxbridge and South Ruislip, stepping down as mayor the following year. In 2016, Johnson became a prominent figure in the successful Vote Leave campaign to withdraw the United Kingdom from the European Union.
Johnson is a controversial figure in British politics and journalism. Supporters have praised him as an entertaining, humorous, and popular figure with appeal beyond traditional Conservative voters. Conversely, he has been criticised by figures on both the left and right, accused of elitism, cronyism and laziness, and using racist language. Johnson is the subject of several biographies and a number of fictionalised portrayals., The Mayor of London is an elected politician who, along with the London Assembly of 25 members, is accountable for the strategic government of Greater London. The current mayor is Sadiq Khan, who took up office on 9 May 2016. The position had been held by Ken Livingstone from the creation of the role on 4 May 2000 until he was defeated in 2008 by Boris Johnson, who served two terms before being succeeded by Khan., The London Assembly is an elected body, part of the Greater London Authority, that scrutinises the activities of the Mayor of London and has the power, with a two-thirds majority, to amend the Mayor's annual budget and to reject the Mayor's draft statutory strategies. The assembly was established in 2000 and meets at City Hall on the South Bank of the River Thames, close to Tower Bridge. The assembly is also able to investigate other issues of importance to Londoners (transport, environmental matters, etc.), publish its findings and recommendations, and make proposals to the Mayor., Subject: london mayoral election, Relation: instance_of, Options: (A) 25 (B) assembly (C) bridge (D) budget (E) city (F) class (G) college (H) council (I) election (J) government (K) house (L) june (M) language (N) line (O) may (P) mayor (Q) mayoral election (R) member (S) october (T) office (U) parliament (V) part (W) politician (X) position (Y) river (Z) role ([) secretary of state (\) sector (]) sentiment (^) stance (_) state (`) union (a) wing (b) writing
mayoral election