Maria Thins
Maria Thins( c. 1593 – 27 December 1680) was the mother- in- law of Johannes Vermeer and a member of the Gouda Thins family.
Ada of Scotland
Ada of Scotland (– after 1206), also known as Ada of Huntingdon, was a member of the Scottish royal house who became Countess of Holland by marriage to Floris III, Count of Holland.
Baroness Gösta von dem Bussche-Haddenhausen
Baroness Gösta von dem Bussche- Haddenhausen( 26 January 1902 – 13 June 1996) was the mother of Prince Claus of the Netherlands, who was the Prince Consort of Queen Beatrix of the Netherlands, thus making her the mother- in- law of the former Dutch Queen.
She is also the paternal grandmother of King Willem- Alexander of the Netherlands, who is the current Dutch King.
William I, Count of Holland
William I( c. 1167 – 4 February 1222), Count of Holland from 1203 to 1222.
He was the younger son of Floris III and Ada of Huntingdon.
Marian Shields Robinson
Marian Lois Robinson( née Shields; born July 29, 1937) is the mother of Michelle Obama, former First Lady of the United States, and Craig Robinson, a basketball executive, and the mother- in- law of former U.S. President Barack Obama.
Doria Ragland
Doria L. Ragland( born September 2, 1956) is the mother of Meghan, Duchess of Sussex, the mother- in- law of Prince Harry, and the maternal grandmother of Archie Mountbatten- Windsor, who is seventh in line to the British throne.
She is a former makeup artist, business owner, yoga instructor, and former social worker who worked in the mental health sector from 2015 to 2018.
Priscilla Pointer
Priscilla Marie Pointer( born May 18, 1924) is an American stage, film and television character actress.
She began her career in the theater, including productions on Broadway.
Later, Pointer moved to Hollywood to act in films and on television.
She is the mother of Amy Irving, therefore making her the former mother- in- law of filmmakers Steven Spielberg and Bruno Barreto and the mother- in- law of documentary filmmaker Kenneth Bowser, Jr.
Eldon Howard
Eldon Howard was a British screenwriter.
She was the mother- in- law of Edward J. Danziger and wrote a number of the screenplays for films by his company Danziger Productions.
Floris III, Count of Holland
Floris III of Holland (1141 – August 1, 1190), Count of Holland from 1157 to 1190.
He was a son of Dirk VI and Sophia of Rheineck, heiress of Bentheim.
Vera Miletić
Vera Miletić (Serbian Cyrillic: Вера Милетић; 8 March 1920 – 7 September 1944) was a Serbian student and soldier.
She was notable for being the mother of Mira Marković, posthumously making her the mother-in-law of Serbian president Slobodan Milošević.

Question: Who is the mother-in-law of Ada Of Scotland?
Answer: Sophia of Rheineck