Question: Who is the maternal grandfather of Hans Albrecht, Hereditary Prince Of Schleswig-Holstein?

Knowledge 1: Hans Albrecht, Hereditary Prince of Schleswig-Holstein
Hans Albrecht, Hereditary Prince of Schleswig-Holstein-Sonderburg-Glücksburg, since 1931 of Schleswig-Holstein (12 May 1917, Schloss Louisenlund, Schleswig, Schleswig-Holstein, Germany – 10 August 1944, Zedlinsk, Poland) was the Hereditary Prince of Schleswig-Holstein and the heir apparent to the Head of the House of Oldenburg.Hans Albrecht was the eldest son of Wilhelm Friedrich, Duke of Schleswig-Holstein and his wife Princess Marie Melita of Hohenlohe-Langenburg.The Hereditary Prince fought in the Second World War between 1939 and 1944 when he died from wounds received in action near Zedlinsk, Poland. [SEP] Knowledge 2: Princess Marie Melita of Hohenlohe-Langenburg
Princess Marie Melita of Hohenlohe-Langenburg (18 January 1899, Langenburg, Württemberg – 8 November 1967, Munich, Germany) was the Duchess consort of Schleswig-Holstein as the wife of Wilhelm Friedrich, Duke of Schleswig-Holstein.She was the eldest daughter of Ernst II, Prince of Hohenlohe-Langenburg and his wife Princess Alexandra of Saxe-Coburg and Gotha.
Knowledge 1: Hans Albrecht, Hereditary Prince of Schleswig-Holstein
Hans Albrecht, Hereditary Prince of Schleswig-Holstein-Sonderburg-Glücksburg, since 1931 of Schleswig-Holstein (12 May 1917, Schloss Louisenlund, Schleswig, Schleswig-Holstein, Germany – 10 August 1944, Zedlinsk, Poland) was the Hereditary Prince of Schleswig-Holstein and the heir apparent to the Head of the House of Oldenburg.Hans Albrecht was the eldest son of Wilhelm Friedrich, Duke of Schleswig-Holstein and his wife Princess Marie Melita of Hohenlohe-Langenburg.The Hereditary Prince fought in the Second World War between 1939 and 1944 when he died from wounds received in action near Zedlinsk, Poland. [SEP] Knowledge 2: Wilhelm Friedrich, Duke of Schleswig-Holstein
Friedrich, Duke of Schleswig- Holstein- Sonderburg- Glücksburg, from 1934 Duke of Schleswig- Holstein( 23 August 1891 – 10 February 1965), was the Duke of Schleswig- Holstein and Head of the House of Oldenburg from 21 January 1934 until his death on 10 February 1965.
Knowledge 1: Hans Albrecht, Hereditary Prince of Schleswig-Holstein
Hans Albrecht, Hereditary Prince of Schleswig-Holstein-Sonderburg-Glücksburg, since 1931 of Schleswig-Holstein (12 May 1917, Schloss Louisenlund, Schleswig, Schleswig-Holstein, Germany – 10 August 1944, Zedlinsk, Poland) was the Hereditary Prince of Schleswig-Holstein and the heir apparent to the Head of the House of Oldenburg.Hans Albrecht was the eldest son of Wilhelm Friedrich, Duke of Schleswig-Holstein and his wife Princess Marie Melita of Hohenlohe-Langenburg.The Hereditary Prince fought in the Second World War between 1939 and 1944 when he died from wounds received in action near Zedlinsk, Poland. [SEP] Knowledge 2: Princess Alexandra Victoria of Schleswig-Holstein-Sonderburg-Glücksburg
Princess Alexandra Victoria of Schleswig-Holstein- Sonderburg- Glücksburg( 21 April 1887 – 15 April 1957) was a daughter of Friedrich Ferdinand, Duke of Schleswig- Holstein and his wife Princess Karoline Mathilde of Schleswig- Holstein- Sonderburg- Augustenburg.

Answer: Ernst II, Prince of Hohenlohe-Langenburg