Question: which sultan of the Ottoman Empire was  Gevherhan Sultan her granddaughter 

Context:
Treaty of London (1827)
The Treaty of London was signed by the United Kingdom, France, and Russia on 6 July 1827.
 The three main European powers had called upon Greece and the Ottoman Empire (Turkey) to cease hostilities that had been going on since the Greeks had revolted against Ottoman rule on 6 March 1821.
 After years of negotiation, the European allied powers had finally decided to intervene in the war on the side of the Greeks.
 The allied powers mainly wanted this treaty to cause the Ottoman Empire to create an independent Greek state.
 It stated that while the Ottoman Empire should recognize the independence of Greece, the Sultan would be the supreme ruler of Greece.
 The treaty declared the intention of the three Allied powers to mediate between the Greeks and the Ottoman Turks.
 The base arrangement was that Greece would become a dependency of Turkey and pay tribute as such Additional articles were added to detail the response should the Turkish Sultan refuse the offer of mediation and continue hostilities in Greece.
 These articles detailed that the Turks had 1 month to accept the mediation or that the Allied powers would form a partnership with the Greeks through commercial relations.
 Measures were also adopted that if the Ottoman Sultan refused the armistice, the Allies would use the appropriate force to ensure the adoption of the armistice.
Selim III
Selim III (Ottoman Turkish: سليم ثالث "Selīm-i sālis") (24 December 1761 – 28 July 1808) was the reform-minded Sultan of the Ottoman Empire from 1789 to 1807.
 The Janissaries eventually deposed and imprisoned him, and placed his cousin Mustafa on the throne as Mustafa IV.
 Selim was killed by a group of assassins subsequenSelim III was the son of Sultan Mustafa III and his wife Mihrişah Sultan.
 His mother Mihrişah Sultan originated in Georgia and when she became the Valide Sultan, she participated in reforming the government schools and establishing political corporations.
 His father Ottoman Sultan Mustafa III was very well educated and believed in the necessity of reforms.
 Mustafa III attempted to create a powerful army during the peacetime with professional, well-educated soldiers.
 This was primarily motivated by his fear of a Russian invasion.
 During the Turko-Russian War he fell ill and died of a heart attack in 1774.
 Sultan Mustafa was aware of the fact that a military reform was necessary.
 He declared new military regulations and opened maritime and artillery academies.
Hurrem Sultan
Hürrem Sultan (] , Ottoman Turkish: خرم سلطان‎ , "Ḫurrem Sulṭān"; 1502 – 15 April 1558) was the favourite and later the chief consort and legal wife of Ottoman Sultan Süleyman the Magnificent.
 She had six children with Süleyman: Şehzade Mehmed, Mihrimah Sultan, Şehzade Abdullah, Sultan Selim II, Şehzade Bayezid, and Şehzade Cihangir.
 She was one of the most powerful and influential women in Ottoman history and a prominent and controversial figure during the era known as the Sultanate of Women.
 She was "Haseki Sultan" (favorite of the Sultan) when her husband, Süleyman I, reigned as the Ottoman sultan.
 She achieved power and influenced the politics of the Ottoman Empire through her husband and played an active role in state affairs of the Empire.
Nefise Hatun
Nefise Hatun, Nefise Sultan, Nefise Melek Hatun, or Nefise Melek Sultan Hatun ( 1363 - 1400) was an Ottoman princess, the daughter of Sultan Murad I of the Ottoman Empire.
 She was married to Prince Alaeddin Ali of Karaman, who was a rival of the rising Ottoman Empire and became the mother of the next Karamanid ruler, Mehmed II of Karaman, who was married to Princess Incu Hatun, the daughter of Ottoman Sultan Mehmed I.
 Her marriage served an alliance between the Ottomans and the Karamanids.
Fatma Sultan (daughter of Selim II)
Fatma Sultan (1559–1580; Ottoman Turkish: فاطمہ سلطان) was an Ottoman princess, daughter of Sultan Selim II (reign 1566–74) of the Ottoman Empire.
 She was the granddaughter of Suleiman the Magnificent (reign 1520–66) and Hürrem Sultan, sister of Sultan Murad III (reign 1574–95) and aunt of Sultan Mehmed III (reign 1595–1603).
Abdulmejid I
Abdülmecid I (Ottoman Turkish: عبد المجيد اول "‘Abdü’l-Mecīd-i evvel"; 23/25 April 182325 June 1861), also known as Abdulmejid and similar spellings, was the 31st Sultan of the Ottoman Empire and succeeded his father Mahmud II on 2 July 1839.
 His reign was notable for the rise of nationalist movements within the empire's territories.
 Abdulmejid wanted to encourage Ottomanism among the secessionist subject nations and stop the rise of nationalist movements within the empire, but failed to succeed despite trying to integrate non-Muslims and non-Turks more thoroughly into Ottoman society with new laws and reforms.
 He tried to forge alliances with the major powers of Western Europe, namely the United Kingdom and France, who fought alongside the Ottoman Empire in the Crimean War against Russia.
 In the following Congress of Paris on 30 March 1856, the Ottoman Empire was officially included among the European family of nations.
 Abdulmejid's biggest achievement was the announcement and application of the Tanzimat "(reorganization)" reforms which were prepared by his father and effectively started the modernization of the Ottoman Empire in 1839.
 For this achievement, one of the Imperial anthems of the Ottoman Empire, the March of Abdulmejid, was named after him.
Suleiman the Magnificent
Suleiman I (Ottoman Turkish: سلطان سليمان اول‎ "Sultan Süleyman-ı Evvel"; Turkish: "I. Süleyman, Kanunî Sultan Süleyman "or" Muhteşem Süleyman" ; 6 November 1494 – 6 September 1566), commonly known as Suleiman the Magnificent in the West and Kanunî Sultan Süleyman (Ottoman Turkish: قانونى سلطان سليمان‎) (English: "The Lawgiver Suleiman") in his realm, was the tenth and longest-reigning sultan of the Ottoman Empire from 1520 to his death in 1566.
 Under his administration, the Ottoman state ruled over 15 to 25 million people.
Turhan Hatice Sultan
Turhan Hatice Sultan (c. 1627 – 4 August 1683; "Turhan" meaning "Of mercy"), was Haseki Sultan of the Ottoman Sultan Ibrahim (reign 1640–48) and Valide Sultan as the mother of Mehmed IV (reign 1648–87).
 Turhan Hatice was prominent for the regency of her young son and her building patronage.
 She and her mother-in-law, Kösem Sultan, are the only two women in Ottoman history to be regarded as official regents and had supreme control over the Ottoman Empire.
 Turhan Hatice herself was the only one in Ottoman history to equally share the power of running the entire empire with Ottoman Sultan legally, although in fact she transferred her political power to the grand vizier.
 As a result, Turhan became one of the prominent figures during the era known as Sultanate of Women.
Gevherhan Sultan (daughter of Ahmed I)
Gevherhan Sultan (Ottoman Turkish: کوھرخان سلطان‎ , 1605 - 1631) was an Ottoman princess, the daughter of Sultan Ahmed I (reign 1603–17) and his favourite consort Kösem Sultan.
Gevherhan Sultan (daughter of Selim II)
Gevherhan Sultan (born 1544, Ottoman Turkish: کوھرخان سلطان‎ ) was an Ottoman princess, the daughter of Sultan Selim II (reign 1566—1574) and Nurbanu Sultan.
 She was the granddaughter of Suleiman the Magnificent (reign 1520–66) and Hürrem Sultan, sister of Sultan Murad III (reign 1574–95) and aunt of Sultan Mehmed III (reign 1595–1603).

Answer: Suleiman I