Duchess Elisabeth of Württemberg (b. 1933)
Duchess Elisabeth of Württemberg( born 2 February 1933) is a member of the House of Württemberg and a Duchess of Württemberg by birth and through her marriage to Prince Antoine of Bourbon- Two Sicilies, a member of the House of Bourbon- Two Sicilies and a Princess of Bourbon- Two Sicilies.
Princess Maria Immaculata of Bourbon-Two Sicilies (1874–1947)
Princess "Maria Immaculata"
Cristina Pia Isabella of Bourbon-Two Sicilies (Full Italian name: "
Maria Immacolata Speranza Pia Teresa Cristina Filomena Lucia Anna Isabella Cecilia Apollonia Barbara Agnese Zenobia,
Principessa di Borbone delle
Due Sicilie")
(30 October 1874 – 28 November 1947) was the fourth child and eldest daughter of Prince Alfonso of Bourbon-Two Sicilies, Count of Caserta and his wife Princess Maria Antonietta of Bourbon-Two Sicilies.
Prince Philip of Bourbon-Two Sicilies
Prince Philip of Bourbon- Two Sicilies( Filippo Maria Alfonso Antonio Ferdinando Francesco di Paola Lodovico Enrico Alberto Taddeo Francesco Saverio Uberto; 10 December 1885 – 9 March 1949) was a member of the House of Bourbon- Two Sicilies and a Prince of Bourbon- Two Sicilies.
Princess Maria Immaculata of Bourbon-Two Sicilies (1844–1899)
Princess Maria Immaculata of Bourbon- Two Sicilies( Full Italian name:" Maria Immacolata Clementina, Principessa di Borbone delle Due Sicilie")( 14 April 1844, Naples, Kingdom of the Two Sicilies – 18 February 1899, Vienna, Austria) was fifth child and second- eldest daughter of Ferdinand II of the Two Sicilies and his wife Maria Theresa of Austria.
Through her marriage to Archduke Karl Salvator of Austria, Maria Immaculata became an Austrian Archduchess.
Princess Urraca of Bourbon-Two Sicilies
Princess Urraca of Bourbon- Two Sicilies( July 14, 1913, Nymphenburg Palace, Munich, Kingdom of Bavaria – May 3, 1999, Sigmaringen, Baden- Württemberg, Germany) was a member of the House of Bourbon- Two Sicilies and a Princess of Bourbon- Two Sicilies.
Maria Carolina Zamoyska
Princess Maria Carolina of Bourbon- Two Sicilies, Duchess of Castro( née Countess Maria Carolina Zamoyska)( 22 September 1896 in Kraków, Austria- Hungary – 9 May 1968 in Marseille, France) was the wife of Prince Ranieri, Duke of Castro, claimant to the headship of the House of Bourbon- Two Sicilies.
Carolina was the sixth child and youngest daughter of Polish nobleman Andrzej Przemysław Zamoyski, Count Zamoyski and his wife Princess Maria Carolina of Bourbon- Two Sicilies.
Carolina's maternal grandparents were Prince Francis of Bourbon- Two Sicilies, Count of Trapani and his wife Archduchess Maria Isabella of Austria, Princess of Tuscany.
Prince Carlo, Duke of Castro
Prince Carlo of Bourbon- Two Sicilies, Duke of Castro( born 24 February 1963) is a claimant to the headship of the House of Bourbon- Two Sicilies.
Prince Alfonso, Count of Caserta
Prince "Alfonso", Count of Caserta (28 March 1841 – 26 May 1934) was the third son of Ferdinand II of the Two Sicilies and Archduchess Maria Theresa of Austria.
He was pretender to the throne of the Two Sicilies in succession of his older half-brother, Francis II of the Two Sicilies.
He was succeeded by his eldest son, Ferdinand Pius.
Leopold, Prince of Salerno
Leopoldo Giovanni Giuseppe Michele of Bourbon- Two Sicilies, Prince of Salerno( 2 July 1790, Naples, Kingdom of Naples – 10 March 1851, Naples, Kingdom of the Two Sicilies) was a member of the House of Bourbon- Two Sicilies and a Prince of Bourbon- Two Sicilies.
Prince Louis, Count of Aquila
Prince "Luigi" Carlo Maria Giuseppe of Bourbon-Two Sicilies, Count of Aquila (19 July 1824 – 5 March 1897) was a member of the House of Bourbon-Two Sicilies.

Question: Who is Princess Maria Immaculata Of Bourbon-Two Sicilies (1874–1947)'s paternal grandfather?
Answer: Ferdinand II of the Two Sicilies