Question: In what country is the county where Arthur Lindsay Sadler was born?

full_context: Document 1: Hackney Empire: The Hackney Empire is a theatre on Mare Street, in the London Borough of Hackney, built in 1901 as a music hall.
Document 2: Ambit Energy: Ambit Energy is an International multi-level marketing company that provides electricity and natural gas services in energy markets in the U.S. that have been deregulated.The company's corporate headquarters are located in Dallas, Texas, and its operations/call center headquarters are located in Plano, Texas. Ambit Energy was founded in 2006 in Addison, Texas by Jere Thompson Jr. and Chris Chambless.
Document 3: John Slade (field hockey): John Slade was born Hans Schlesinger in Frankfurt, Germany on May 30, 1908. According to Slade, his was a family of "highly assimilated Jews." He was expected to compete in the 1936 Olympics in Berlin but could not due to the Nuremberg Laws. Leaving Germany for New York, he was able to get a $15-a-week messenger job at the investment firm of Bear, Stearns. By 1940, he was working in risk arbitrage and had earned enough to bring his family to America. In 1942, he volunteered for the United States Army.
Document 4: Harold Marks: Harold Marks was born in London and educated at Caterham School, University College, Oxford (BA in Modern Greats), and Wesleyan University, Connecticut. At Oxford he fell under the influence of G. D. H. Cole and Sandy Lindsay. He began his career in adult education in south Wales before taking up an appointment as Oxford University extramural tutor in Staffordshire 1936–42.
Document 5: Arthur Lindsay Sadler: Sadler was born in Hackney, London. He was educated at Dulwich College, Merchant Taylors' School, London, and St John's College, Oxford (B.A., 1908; M.A., 1911). He was Pusey-Ellerton Hebrew scholar (1903), junior Kennicott Hebrew scholar (1907), won the junior Septuagint prize (1907) and graduated with second-class honours in Oriental languages (Hebrew and Assyrian).
Document 6: Cascade AIDS Project: Cascade AIDS Project (CAP) is a nonprofit organization based in Portland, Oregon, in the United States. Its mission is to prevent HIV infections, to "support and empower" people affected and by HIV/AIDS, and to eliminate stigma associated with the disease. Founded in 1983 and incorporated two years later, CAP is the "oldest and largest community-based provider of HIV services, housing, education and advocacy" in Oregon and Southwest Washington.
Document 7: Harold Arthur Harris: Professor Harold Arthur Harris (27 October 1902 – 29 August 1974) was educated at Oxford High School, and went on to study at Jesus College, Oxford. Here, he gained a first in Classical Moderations, becoming a senior scholar, and graduating with first class honours in English.
Document 8: Cape plc: Cape plc is a United Kingdom energy services company based in West Drayton, Middlesex. It was acquired by Altrad in September 2017.
Document 9: Hackney, Guyana: Hackney, is a village in Guyana, standing on the eastern bank of the Pomeroon River, 11 km from its mouth. Formerly the business centre for residents of the coconut estates of the lower Pomeroon River, Hackney is still of some importance. It provides a primary school and church for residents of the surrounding area.
Document 10: Capita: Capita was formed 1984 as a division of the non-profit CIPFA (Chartered Institute of Public Finance and Accountancy). In 1987 it became an independent company with 33 staff as a result of a management buy - out, led by Rod Aldridge, and was first listed on the London Stock Exchange in 1991.
Document 11: Hackney (parish): Hackney was a parish in the historic county of Middlesex. The parish church of St John-at-Hackney was built in 1789, replacing the nearby former 16th-century parish church dedicated to St Augustine (pulled down in 1798). The original tower of that church was retained to hold the bells until the new church could be strengthened; the bells were finally removed to the new St John's in 1854. See details of other, more modern, churches within the original parish boundaries below.
Document 12: George Salting: George Salting was educated locally and then moved with his family to England and studied at Eton College. In 1853 the family returned to New South Wales, and Salting entered the newly founded University of Sydney. There he won prizes for compositions in Latin hexameters in 1855 and 1857, in Latin elegiacs in 1856, 1857 and 1858, and for Latin essays in 1854 and 1856. Salting graduated with a Bachelor of Arts degree in 1857. In 1858 the Salting family again travelled to England; Louisa Salting died there on 24 July 1858. Severin Salting settled in Kent, where he died in 1865. Severin Salting made a large fortune in sheep-farming and sugar-growing which he bequeathed to his son; George Salting inherited a fortune estimated at £30,000 a year.
Document 13: St Anne and St Agnes: St Anne and St Agnes was rebuilt by Sir Christopher Wren in 1680, with possible contributions from Robert Hooke. The small brick church is of an unusual design in London, being based on that of a Greek cross; it utilises a vaulted square within a square, a formula based on the Nieuwe Kerk in Haarlem in the Netherlands. Wren also used a similar design at St Martin Ludgate and St Mary-at-Hill. The parish was united with the parish of St John Zachary by Act of Parliament in 1670 as St John's was not rebuilt after the Great Fire.
Document 14: All-Hallows-the-Great: All-Hallows-the-Great was a church in the City of London, located on what is now Upper Thames Street, first mentioned in 1235. Destroyed in the Great Fire of London of 1666, the church was rebuilt by the office of Sir Christopher Wren. All-Hallows-the-Great was demolished in 1894 when many bodies were disinterred from the churchyard and reburied at Brookwood Cemetery.
Document 15: Capita: It is the largest business process outsourcing and professional services company in the UK, with an overall market share of 29% in 2016, and has clients in central government, local government and the private sector. It also has a property and infrastructure consultancy division which is the fourth largest multidisciplinary consultancy in the UK. Roughly half of its turnover comes from the private sector and half from the public sector. Whilst UK-focused, Capita also has operations across Europe, Africa and Asia.
ground_truth: United Kingdom
sub_queries: Arthur Lindsay Sadler >> place of birth Answer: Hackney
Hackney >> located in the administrative territorial entity Answer: Middlesex
Middlesex >> country Answer: United Kingdom