Question:  Princess Alexandra of Hanover is the only child of the Duke of what areas?
Context: Thatched House Lodge is a Grade II-listed building, dating from the 17th century, in Richmond Park in the London Borough of Richmond upon Thames in London, England.  It was the home of British Prime Minister Sir Robert Walpole and, since 1963, has been a royal residence, being leased from the Crown Estate by Princess Alexandra, The Honourable Lady Ogilvy (born Princess Alexandra of Kent) and, until his death in 2004, her husband Sir Angus Ogilvy. Grand Duchess Alexandra Georgievna of Russia (Russian: Алекса́ндра Гео́ргиевна ); "née" Princess Alexandra of Greece and Denmark (Greek: Πριγκίπισσα Αλεξάνδρα της Ελλάδας και της Δανίας ); 30 August 1870 – 24 September 1891) was the third child and firstborn daughter of King George I and Queen Olga of Greece, who herself was a daughter of a Russian grand duke, and was also a grandchild of Denmark's King Christian IX and Queen Louise.  She was a sister to Constantine I of Greece, and thus aunt of three kings and two queens, Constantine's three sons, who all became kings of Greece, and two of his daughters, who were queens, in name, of Romania and Croatia, respectively.  She was also first cousin of Tsar Nicholas II of Russia, King George V of the United Kingdom, and both King Haakon VII and Queen Maud of Norway, as well as a paternal aunt of Prince Philip, Duke of Edinburgh. Princess Olga was born at Stuttgart, Württemberg, the younger twin daughter of Duke Eugen of Württemberg (1846–1877), (son of Duke Eugen of Württemberg, and Princess Mathilde of Schaumburg-Lippe) and his wife, Grand Duchess Vera Constantinovna of Russia (1854–1912), (daughter of Grand Duke Konstantin Nikolayevich of Russia and Princess Alexandra of Saxe-Altenburg).  Her older twin was Duchess Elsa of Württemberg (1876–1932).  They did not look alike and Olga, much taller than her sister, seemed to be the elder of the two. The Princess Alexandra Hospital NHS Trust serves a population of 258,000 & provides healthcare services to the communities of Harlow and the surrounding areas.  It runs Princess Alexandra Hospital in Harlow, Essex, England.  It is a 501 bedded District General Hospital providing a comprehensive range of acute and specialist services to a local population of 258,000 people.  It has been led since May 2017 by Alan Burns (Chairman) and Lance McCarthy (Chief Executive).  It has a hospital radio station, Harlow Hospital Radio. Princess Alexandra of Hanover and Cumberland ("German: Alexandra Louise Marie Olga Elisabeth Therese Vera Prinzessin von Hannover und Cumberland"; 29 September 1882 – 30 August 1963) was the wife of Frederick Francis IV, Grand Duke of Mecklenburg-Schwerin, the last ruling Duke of Mecklienburg-Schwerin. Ernst August, Prince of Hanover, Duke of Brunswick and Lüneburg ("Ernst August Albert Paul Otto Rupprecht Oskar Berthold Friedrich-Ferdinand Christian-Ludwig Prinz von Hannover Herzog zu Braunschweig und Lüneburg Königlicher Prinz von Großbritannien und Irland"; born 26 February 1954) is head of the deposed royal House of Hanover which held the thrones of the United Kingdom until 1901, of the former Kingdom of Hanover until 1866 and of the sovereign Duchy of Brunswick (1913 to 1918).  As the husband of Princess Caroline of Monaco, he is the brother-in-law of Albert II, Prince of Monaco.  His wealth is estimated at £5 billion. Princess Alexandra of Hanover (Alexandra Charlotte Ulrike Maryam Virginia; born 20 July 1999) is the only child of Princess Caroline of Monaco and Prince Ernst August, heir to the throne of the defunct Kingdom of Hanover.  She was born in Vöcklabruck, Upper Austria. Duchess Anastasia Alexandrine Cecile Marie Luise Wilhelmine of Mecklenburg-Schwerin (Full German name: "Anastasia Alexandrine Cecile Marie Luise Wilhelmine Herzogin zu Mecklenburg-Schwerin"), (11 November 1923, Gelbensande, Free State of Mecklenburg-Schwerin, Weimar Republic – 25 January 1979, Hamburg, West Germany).  Anastasia was the youngest child and youngest daughter of Frederick Francis IV, Grand Duke of Mecklenburg-Schwerin and his wife Princess Alexandra of Hanover and Cumberland. Princess Alexandra of Hanover (German: "Alexandra Irene Margaretha Elisabeth Bathildis, Prinzessin von Hannover" ), Duchess of Brunswick-Lüneburg, Princess of Leiningen (born 18 February 1959) is the wife of Andreas, 8th Prince of Leiningen. Elizabeth at 90: A Family Portrait is a 2016 television documentary film made to commemorate the 90th birthday of Queen Elizabeth II.  It was produced by the BBC and directed by John Bridcut, and narrated by Charles, Prince of Wales.  Aside from archive footage, the programme featured extensive footage shot by the Queen, Prince Philip, Duke of Edinburgh, Princess Margaret, King George VI and Queen Elizabeth the Queen Mother.  The footage had never been publicly shown and came from the Queen's private archive of homemade films.  The footage shown was interspersed with members of the British royal family commenting on the films.  The film featured contributions from the Queen, the Prince of Wales, Anne, Princess Royal, Prince William, Duke of Cambridge and Prince Harry, Lady Sarah Chatto, Prince Edward, Duke of Kent and Princess Alexandra, The Honourable Lady Ogilvy.
Answer: Brunswick and Lüneburg