Question: Who is Sibyl Hathaway's child-in-law?

Knowledge 1: Sibyl Hathaway
Dame Sibyl Mary Hathaway ("née" Collings; 13 January 1884 – 14 July 1974) was Dame of Sark from 1927 until her death in 1974.Her 47-year rule over Sark, in the Channel Islands, spanned the reigns of four Monarchs: George V, Edward VIII, George VI and Elizabeth II.Hathaway was a financially troubled widow with six children when she succeeded her eccentric father, William Frederick Collings, as feudal lady of Sark.She immediately set about reinforcing her feudal rights and promoting tourism on the island, which she affectionately called "the last bastion of feudalism".When she remarried in 1929, her second husband, Robert Hathaway, legally became her senior co-ruler, but she kept control of the government.Hathaway's tenure saw the German occupation of the Channel Islands in the Second World War, during which she refused to evacuate and convinced the islanders to stay as well.Her eldest son and heir apparent, Francis William Beaumont, was killed in 1941, while her husband was deported to an internment camp in 1943.Hathaway remains best known for her indomitable conduct during the occupation.After the war, she continued her publicity campaign, strengthening the island's tourism industry.Having been widowed again in 1954, she went on to rule alone, and was made Dame Commander of the Order of the British Empire in 1965.She was described by a British government official as a "lady of unusual personality", and is often referred to as a benevolent dictator.Dame Sibyl died at the age of 90, and was succeeded by her grandson, Michael Beaumont. [SEP] Knowledge 2: Francis William Beaumont
Francis William Lionel Collings Beaumont (6 August 1903 – 4 May 1941), also known as F. W. L. C. Beaumont or “Buster" Beaumont, was the heir to the Seigneur of Sark, a Royal Air Force officer, film producer and the husband of actress Mary Lawson.He and Lawson were killed in 1941 during the Liverpool Blitz.
Knowledge 1: Sibyl Hathaway
Dame Sibyl Mary Hathaway ("née" Collings; 13 January 1884 – 14 July 1974) was Dame of Sark from 1927 until her death in 1974.Her 47-year rule over Sark, in the Channel Islands, spanned the reigns of four Monarchs: George V, Edward VIII, George VI and Elizabeth II.Hathaway was a financially troubled widow with six children when she succeeded her eccentric father, William Frederick Collings, as feudal lady of Sark.She immediately set about reinforcing her feudal rights and promoting tourism on the island, which she affectionately called "the last bastion of feudalism".When she remarried in 1929, her second husband, Robert Hathaway, legally became her senior co-ruler, but she kept control of the government.Hathaway's tenure saw the German occupation of the Channel Islands in the Second World War, during which she refused to evacuate and convinced the islanders to stay as well.Her eldest son and heir apparent, Francis William Beaumont, was killed in 1941, while her husband was deported to an internment camp in 1943.Hathaway remains best known for her indomitable conduct during the occupation.After the war, she continued her publicity campaign, strengthening the island's tourism industry.Having been widowed again in 1954, she went on to rule alone, and was made Dame Commander of the Order of the British Empire in 1965.She was described by a British government official as a "lady of unusual personality", and is often referred to as a benevolent dictator.Dame Sibyl died at the age of 90, and was succeeded by her grandson, Michael Beaumont. [SEP] Knowledge 2: Robert Vadra
Robert Vadra is an Indian businessman, entrepreneur and the husband of Priyanka Gandhi.He is the son -in- law of Sonia Gandhi and Rajiv Gandhi, and the brother- in- law of Rahul Gandhi.
Knowledge 1: Sibyl Hathaway
Dame Sibyl Mary Hathaway ("née" Collings; 13 January 1884 – 14 July 1974) was Dame of Sark from 1927 until her death in 1974.Her 47-year rule over Sark, in the Channel Islands, spanned the reigns of four Monarchs: George V, Edward VIII, George VI and Elizabeth II.Hathaway was a financially troubled widow with six children when she succeeded her eccentric father, William Frederick Collings, as feudal lady of Sark.She immediately set about reinforcing her feudal rights and promoting tourism on the island, which she affectionately called "the last bastion of feudalism".When she remarried in 1929, her second husband, Robert Hathaway, legally became her senior co-ruler, but she kept control of the government.Hathaway's tenure saw the German occupation of the Channel Islands in the Second World War, during which she refused to evacuate and convinced the islanders to stay as well.Her eldest son and heir apparent, Francis William Beaumont, was killed in 1941, while her husband was deported to an internment camp in 1943.Hathaway remains best known for her indomitable conduct during the occupation.After the war, she continued her publicity campaign, strengthening the island's tourism industry.Having been widowed again in 1954, she went on to rule alone, and was made Dame Commander of the Order of the British Empire in 1965.She was described by a British government official as a "lady of unusual personality", and is often referred to as a benevolent dictator.Dame Sibyl died at the age of 90, and was succeeded by her grandson, Michael Beaumont. [SEP] Knowledge 2: Nancy Lancaster
Nancy Lancaster( 10 September 1897 – 19 August 1994) was a 20th- century tastemaker and the owner of Sibyl Colefax& John Fowler, an influential British decorating firm that codified what is known as the English country house look.

Answer: Mary Lawson