Question: What island in Denmark has 39% of the country's population and contains a mansion with an 8 hectare park?
Context: Narborough Railway Line is a former railway line, now a reserve near King’s Lynn in the county of Norfolk, England.  The Norfolk Wildlife Trust and the British Butterfly Society own and manage Narborough Railway Line.  The 6 to 8 hectare (15 to 20 acre) site is 1 kilometre (0.62 mi) south of Narborough, on the A47 going east from King's Lynn to Swaffham.  The reserve can be entered by a car park west of the reserve.  It was documented in 1847 as an area with lots of chalk and flints. Houghton Meadow is a 4.7 hectare biological Site of Special Scientific Interest (SSSI) between Houghton and St Ives in Cambridgeshire.  The SSSI covers three meadows south of Thicket Road; they are part of the 8 hectare Houghton Meadows nature reserve, which is owned and managed by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire, and which also includes Browns Meadow to the south. Zealand (Danish: "Sjælland" , ] ), at 7,031 km, is the largest (except Greenland) and most populated island in Denmark with a population of 2,267,659 (39% of Denmark's total as of January 2016). South Park is a 7.9 hectare park in the London Borough of Hammersmith and Fulham.  South Park contains a public cricket pitch, tennis courts, football pitches, netball and basketball courts.  In addition there is a large children's playground fenced off from the main park and a 1 km perimeter walk used by runners, walkers, dogs and their owners.  Many people enjoy South Park for its unique trees and well maintained gardens.  A nursery for 2-5 year olds operates out of the cricket pavilion. Lamorbey Park is a 57 hectare park in Lamorbey, in the London Borough of Bexley, set around a Grade II listed mansion, Lamorbey House.  The original 17th century estate consisted of 119 hectares, but over time sections of the estate have been separated for other uses, including two secondary schools (Chislehurst and Sidcup Grammar School and Hurstmere School), Rose Bruford College, and Sidcup Golf Club.  The area of the park still in public ownership includes The Glade, a 7.4 hectare area of historic landscape laid in the 1920s with a large lake.  The park was added to the Register of Historic Parks and Gardens of special historic interest in 1988. Fossli Provincial Park is a provincial park in British Columbia, Canada, located on Stirling Arm of Sproat Lake on Vancouver Island.  The 52-hectare park, west of Port Alberni, is accessible by water or private logging road.  It has few services, but has a 30-minute hiking trail to an old homestead site.  The homestead belonged to Helen and Armour Ford, who donated the land for the park to the province in 1974.  Saint Andrew's Creek runs through the park, and is a fall spawning ground for coho salmon. Stamp River Provincial Park is a provincial park in British Columbia, Canada.  The 327-hectare park is located 14 km north of Port Alberni on Vancouver Island.  There are 23 camping spaces and 2 km of trails within the park along the Stamp River, named for Edward Stamp, a sawmill pioneer in the Alberni Valley. Magleås is a mansion in Høsterkøb near Birkerød in northern Zealand, Denmark.  It is located in Rudersdal Municipality in the Capital Region of Denmark, 25 km.  outside Copenhagen.  The mansion includes 8 hectare park, and borders on the Rude Forest ("Rude Skov").  It also includes stables and a caretaker's house. Oakleigh Park Rail Cutting is an 8 hectare Site of Local Importance for Nature Conservation in Oakleigh Park in the London Borough of Barnet.  It is on the East Coast Main Line between Oakleigh Park railway station and Barnet Tunnel to its south. Pok Fu Lam Country Park is located on Pok Fu Lam, the western end of the Southern District of Hong Kong Island.  The 270-hectare park was designated in 1979.
Answer: Zealand