Question: Which fortress that controlled the entranceway between Kattegat and Øresund was in "Hamlet"?

full_context: Document 1: Hamlet (1996 film): Hamlet is a 1996 film adaptation of William Shakespeare's play "Hamlet", adapted for the screen and directed by Kenneth Branagh, who also stars in the titular role as Prince Hamlet. The film also features Derek Jacobi as King Claudius, Julie Christie as Queen Gertrude, Kate Winslet as Ophelia, Michael Maloney as Laertes, Richard Briers as Polonius, and Nicholas Farrell as Horatio. Other notable appearances include Robin Williams, Gérard Depardieu, Jack Lemmon, Billy Crystal, Rufus Sewell, Charlton Heston, Richard Attenborough, Judi Dench, John Gielgud and Ken Dodd.
Document 2: Kronborg: Kronborg is a castle and stronghold in the town of Helsingør, Denmark. Immortalized as Elsinore in William Shakespeare's play "Hamlet", Kronborg is one of the most important Renaissance castles in Northern Europe and has been added to UNESCO's World Heritage Sites list (2000).
Document 3: Flakfortet: Flakfortet, meaning sand-shoal fortress, is a sea fort located on the artificially built island of "Saltholmrev", in the Øresund between Copenhagen and Saltholm. The island and fort are simply known as "Flakfortet"; the name of the island; "Saltholmrev", meaning the reef near Saltholm, is seldom used.
Document 4: Fort Dansborg: Fort Dansborg, locally called Danish Fort, is a Danish fort located in the shores of Bay of Bengal in Tharangambadi in the South Indian state of Tamil Nadu. Fort Dansborg was built in the land ceded by Thanjavur king Ragunatha Nayak in an agreement with Danish Admiral Ove Gjedde in 1620 and acted as the base for Danish settlement in the region during the early 17th century. The fort is the second largest Danish fort after Kronborg. The fort was sold to the British in 1845 and along with Tharangambadi, the fort lost its significance as the town was not an active trading post for the British. After India's independence in 1947, the fort was used as an inspection bungalow by the state government till 1978 when the Department of Archaeology, Government of Tamil Nadu took over the control of the fort. The fort is now used as a museum where the major artifacts of the fort and the Danish empire are displayed.
Document 5: Literary influence of Hamlet: William Shakespeare's Hamlet is a tragedy, believed to have been written between 1599 and 1601. It tells the story of Hamlet, Prince of Denmark—who takes revenge on the current king (Hamlet's uncle) for killing the previous king (Hamlet's father) and for marrying his father's widow (Hamlet's mother)—and it charts the course of his real or feigned madness. "Hamlet" is the longest play—and Hamlet is the largest part—in the entire Shakespeare canon. Critics say that "Hamlet" "offers the greatest exhibition of Shakespeare's powers".
Document 6: Middelgrundsfortet: Middelgrundsfortet or Fort Middelgrund is a sea fort located on an artificial island in the Øresund between Copenhagen and Malmö. The fortress is constructed at a point where the seabed is 7 meters below the water surface, and at the northern meeting point of the straits Kongedybet and Hollænderdybet.
Document 7: Gyldenstierne (noble family): Gyldenstjerne, also spelled "Gyldenstierne" and in Swedish "Gyllenstierna" (English: "Golden Star"), is a Danish, Norwegian, and Swedish noble family divided into various branches and ranks. It is one of the oldest noble families in Scandinavia. The family surname appears, in the form of "Guildenstern", in William Shakespeare's tragedy "The Tragedy of Hamlet, Prince of Denmark" (see Rosencrantz and Guildenstern).The surname should not be confused with Gyldensteen ("Golden Stone"), the name of another short-lived Danish noble family, first recorded in 1717 and which became extinct in 1749.
Document 8: Kärnan: Kärnan (] ; Danish: "Kernen" , both literally "The Core") is a medieval tower in Helsingborg, Scania, in southern Sweden. It is the only part remaining of a larger Danish fortress which, along with the fortress Kronborg on the opposite of Øresund, controlled the entranceway between Kattegat and Øresund and further south the Baltic Sea.
Document 9: Øresund: Øresund or Öresund (Danish: "Øresund" , ] ; Swedish: "Öresund" , ] ), commonly known in English as the Sound, is a strait which forms the Danish–Swedish border, separating Sjælland (Denmark) from Skåne (Sweden). The strait has a length of 118 km and the width varies from 4 km to 28 km . It is 4 km wide at its narrowest point between Helsingør in Denmark and Helsingborg in Sweden.
Document 10: Horatio (Hamlet): Horatio is a character in William Shakespeare's tragedy "Hamlet". Horatio's origins are unknown, although he was present on the battlefield when Hamlet's father defeated 'the ambitious Norway', Fortinbras (the king), and attended Wittenberg University with Prince Hamlet. Horatio is evidently not directly involved in the intrigue at the Danish court; thus, he makes a good foil or sounding board for Prince Hamlet. He is often not identified as any specific court position, but simply as "friend to Hamlet."
Document 11: Königsberg fortifications: The fortifications of the former East Prussian capital Königsberg (now Kaliningrad) consist of numerous defensive walls, forts, bastions and other structures. They make up the First and the Second Defensive Belt, built in 1626—1634 and 1843—1859, respectively. The 15 metre-thick First Belt was erected due to Königsberg's vulnerability during the Polish–Swedish wars. The Second Belt was largely constructed on the place of the first one, which was in a bad condition. The new belt included twelve bastions, three ravelins, seven spoil banks and two fortresses, surrounded by water moat. Ten brick gates served as entrances and passages through defensive lines and were equipped with moveable bridges.
Document 12: Kastellet, Copenhagen: Kastellet, (English: The Citadel) located in Copenhagen, Denmark, is one of the best preserved star fortresses in Northern Europe. It is constructed in the form of a pentagram with bastions at its corners. Kastellet was continuous with the ring of bastioned ramparts which used to encircle Copenhagen but of which only the ramparts of Christianshavn remain today.
Document 13: Fortinbras: Fortinbras is either of two minor fictional characters from William Shakespeare's tragedy "Hamlet". The more notable is a Norwegian crown prince with a few brief scenes in the play, who delivers the final lines that represent a hopeful future for the monarchy of Denmark and its subjects. Fortinbras is also the name of the former king of Norway and father of the crown prince Fortinbras. King Fortinbras was slain in the play's antecedent action in battle with King Hamlet. The battle between the two is described by Horatio in Act One, Scene One (I,i) of the play.
Document 14: Helsingborg: Helsingborg (] ; spelled Hälsingborg between 1912 and 1970) is a town and the seat of Helsingborg Municipality, Scania, Sweden. It had 132,989 inhabitants in 2013. Helsingborg is the centre of the northern part of western Scania. There is no formal metropolitan area, but the municipality of Helsingborg City and its neighbouring five municipalities (within Scania) had in spring of 2013 a population of 269.489 inhabitants at an area of 1.353 km2 , a population density of 200 people/km. This makes Helsingborg the fourth largest population area in Sweden. The city is also Sweden's closest point to Denmark, with the Danish city Helsingør clearly visible on the other side of the Øresund about 4 km to the west, closer than to the city's own remoter areas. If including all population around the northern part of Øresund, as a Helsingborg-Helsingør metropolitan area, its population increases to 732.450 at an area of 2.802 km2 . The busy ferry route, known as the HH Ferry route has through history been operated by several shipping lines. s of 2014 more than 70 car ferries departures from each harbour every day.
Document 15: Jacob Clement Utzon-Krefeld: Jacob Clement Utzon-Krefeld (born 1990, Denmark) is a Danish actor Played Hamlet in Shakespeare's Hamlet at the Castle of Elsinore for two consecutive years 2016-17. Studied at East 15 Drama School in London.
ground_truth: Kronborg