Question: What is the name of the widow of the earl who served as both Foreign Secretary and Prime Minster from 1955 to 1957?

full_context: Document 1: Winston Churchill: Sir Winston Leonard Spencer-Churchill, {'1': ", '2': ", '3': ", '4': "} (30 November 187424 January 1965) was a British statesman, army officer, and writer. He served as Prime Minister of the United Kingdom from 1940 to 1945 and again from 1951 to 1955. As a Member of Parliament (MP), he represented five constituencies over the course of his career. As Prime Minister, Churchill led Britain to victory during World War II. He led the Conservative Party for fifteen years from 1940 to 1955.
Document 2: Stanley Baldwin: Stanley Baldwin, 1st Earl Baldwin of Bewdley, (3 August 186714 December 1947) was a British Conservative politician who dominated the government in his country between the two world wars. Three times Prime Minister, he is the only premier to have served under three monarchs (George V, Edward VIII and George VI).
Document 3: Anthony Eden: Robert Anthony Eden, 1st Earl of Avon, (12 June 1897 – 14 January 1977) was a British Conservative politician who served three periods as Foreign Secretary and then a relatively brief term as Prime Minister of the United Kingdom from 1955 to 1957.
Document 4: Mary Soames: Mary Soames, Baroness Soames, ("née" Spencer-Churchill; 15 September 1922 – 31 May 2014) was the youngest of the five children of Winston Churchill and his wife, Clementine. She was the wife of Christopher Soames.
Document 5: Anthony Eden hat: An "Anthony Eden" hat, or simply an "Anthony Eden", was a silk-brimmed, black felt Homburg of the kind favoured in the 1930s by Anthony Eden, later 1st Earl of Avon (1897–1977). Eden was a Cabinet Minister in the British National Government, holding the offices of Lord Privy Seal from 1934–1935 and Foreign Secretary 1935 to 1938. He was later Dominions Secretary from 1939–1940, War Secretary in 1940, Foreign Secretary from 1940–1945 and 1951–1955, and Prime Minister 1955 to 1957.
Document 6: Anne Chamberlain: Anne de Vere Chamberlain (née Cole; 1883 – 12 February 1967) was the wife of British Prime Minister Neville Chamberlain.
Document 7: George Curzon, 1st Marquess Curzon of Kedleston: George Nathaniel Curzon, 1st Marquess Curzon of Kedleston (11 January 1859 – 20 March 1925), known as The Lord Curzon of Kedleston between 1898 and 1911 and as The Earl Curzon of Kedleston between 1911 and 1921, was a British Conservative statesman.
Document 8: Neville Chamberlain: Arthur Neville Chamberlain, ( ; 18 March 1869 – 9 November 1940) was a British Conservative politician who served as Prime Minister of the United Kingdom from May 1937 to May 1940. Chamberlain is best known for his appeasement foreign policy, and in particular for his signing of the Munich Agreement in 1938, conceding the German-speaking Sudetenland region of Czechoslovakia to Germany. However, when Adolf Hitler later invaded Poland, the UK declared war on Germany on 3 September 1939, and Chamberlain led Britain through the first eight months of World War II.
Document 9: Clarissa Eden: Anne Clarissa Eden, Dowager Countess of Avon ("née" Spencer-Churchill; born 28 June 1920) is the widow of Anthony Eden, 1st Earl of Avon (1897–1977), who was British Prime Minister from 1955 to 1957. She married Eden in 1952, becoming Lady Eden in 1954 when he was made a Knight of the Garter, and then becoming Countess of Avon in 1961 on her husband's elevation to the peerage. She is also the niece of the prime minister Winston Churchill. Her memoir, sub-titled "From Churchill to Eden", was published in 2007 under the name of Clarissa Eden.
Document 10: Beatrice Beckett: Beatrice Helen Beckett (27 July 1905 – 29 June 1957) was the first wife of the British statesman Anthony Eden.
Document 11: Descendants of Winston Churchill: Sir Winston Churchill, son of Lord Randolph Churchill and grandson of John Spencer-Churchill, 7th Duke of Marlborough, was Prime Minister of the United Kingdom between 26 October 1951 – 6 April 1955 and 10 May 1940 – 26 July 1945. In 1908, Churchill married Clementine Hozier, the daughter of Sir Henry and Lady Blanche Hozier. By Clementine, Churchill had five children and ten grandchildren, a number of whom are well known in their own right.
Document 12: Harold Macmillan: Maurice Harold Macmillan, 1st Earl of Stockton, {'1': ", '2': ", '3': ", '4': "} (10 February 1894 – 29 December 1986) was a British statesman of the Conservative Party who served as Prime Minister of the United Kingdom from 1957 to 1963. Nicknamed "Supermac", he was known for his pragmatism, wit and unflappability.
Document 13: Clementine Churchill: Clementine Ogilvy Spencer-Churchill, Baroness Spencer-Churchill, ("née" Hozier; 1 April 1885 – 12 December 1977) was the wife of Sir Winston Churchill and a life peer in her own right.
Document 14: Conservative government, 1957–1964: The Conservative government of the United Kingdom that began in 1957 and ended in 1964 consisted of three ministries: the first Macmillan ministry, second Macmillan ministry, and then the Douglas-Home ministry. They were led by Harold Macmillan and Sir Alec Douglas-Home, who were appointed respectively by Queen Elizabeth II.
Document 15: John Major: Sir John Major, {'1': ", '2': ", '3': ", '4': "} (born 29 March 1943) is a British politician who was Prime Minister of the United Kingdom and Leader of the Conservative Party from 1990 to 1997. He served as Foreign Secretary and then Chancellor of the Exchequer in the Thatcher Government from 1989 to 1990, and was the Member of Parliament (MP) for Huntingdon from 1979 until he retired in 2001. Since Margaret Thatcher's death in 2013, he is the oldest living former Prime Minister.
ground_truth: Anne Clarissa Eden