Question: The National Stakes is a South Australian horse race held at a racecourse how many kilometers from the Adelaide city center?

Context paragraphs:
Geisha Handicap: Geisha Stakes is an American Thoroughbred horse race held annually in April since 1973 primarily at Pimlico Race Course in Baltimore or at Laurel Park Racecourse in Laurel.  To be eligible for the Geisha Handicap, a horse must be bred in Maryland.  Due to that restriction the race is classified as a non-graded or "listed" stakes race and is not eligible for grading by the American Graded Stakes Committee.

Belmont Stakes: The Belmont Stakes is an American Grade I stakes Thoroughbred horse race held every June at Belmont Park in Elmont, New York.  It is a 1.5 mi horse race, open to three-year-old Thoroughbreds.  Colts and geldings carry a weight of 126 lb ; fillies carry 121 lb .  The race, nicknamed The Test of the Champion, and The Run for the Carnations, is the third and final leg of the Triple Crown and is held five weeks after the Kentucky Derby and three weeks after the Preakness Stakes.  The 1973 Belmont Stakes and Triple Crown winner Secretariat holds the mile and a half stakes record (which is also a track and world record on dirt) of 2:24.

2005 King George VI and Queen Elizabeth Stakes: The 2005 King George VI and Queen Elizabeth Stakes was a horse race held at Newbury Racecourse on Saturday 23 July 2005.  It was the 55th King George VI and Queen Elizabeth Stakes.  The race was run at Newbury as Ascot Racecourse, the event's traditional home, was being redeveloped.  Whereas Ascot is a right-handed, triangular course with a short straight, Newbury is a wide, left-handed oval with a five furlong straight, giving the race a very different complexion.

Auraria Stakes: The Schweppervescence Stakes, registered as the Auraria Stakes is a South Australian Jockey Club Group 3 thoroughbred horse race for three years old fillies raced under Set Weights with penalties conditions, over a distance of 1800 metres at Morphettville Racecourse in Adelaide, Australia.  Total prize money for the race is A$120,000.

Maryland Million Nursery: Maryland Million Nursery is an American Thoroughbred horse race held annually in October since 1986 primarily at Laurel Park Racecourse in Laurel, Maryland or at Pimlico Race Course in Baltimore.  To be eligible for the Maryland Million Nursery, a horse must be sired by a stallion who stands in Maryland.  Due to that restriction the race is classified as a non-graded or "listed" stakes race and is not eligible for grading by the American Graded Stakes Committee.

Maryland Million Oaks: Maryland Million Oaks is an American Thoroughbred horse race held annually in October since 1986 primarily at Laurel Park Racecourse in Laurel, Maryland or at Pimlico Race Course in Baltimore.  To be eligible for the Maryland Million Oaks, a horse must be sired by a stallion who stands in Maryland.  Due to that restriction the race is classified as a non-graded or "listed" stakes race and is not eligible for grading by the American Graded Stakes Committee.

Maryland Million Turf: Maryland Million Turf is an American Thoroughbred horse race held annually in October since 1986 primarily at Laurel Park Racecourse in Laurel, Maryland or at Pimlico Race Course in Baltimore.  To be eligible for the Maryland Million Turf, a horse must be sired by a stallion who stands in Maryland.  Due to that restriction the race is classified as a non-graded or "listed" stakes race and is not eligible for grading by the American Graded Stakes Committee.

National Stakes (SAJC): The National Stakes is a South Australian Jockey Club Group 3 Thoroughbred horse race for horses aged two years old, at set weights with penalties, over a distance of 1200 metres, held annually at Morphettville Racecourse in Adelaide, Australia during the Autumn Carnival.

Morphettville Racecourse: Morphettville Racecourse is the main horse racing track for the Australian state of South Australia.  It is situated in the Adelaide suburb of Morphettville, and is about 10 km from the Adelaide city centre.  It is home to the South Australian Jockey Club.

Maryland Million Sprint Handicap: Maryland Million Sprint Handicap is an American Thoroughbred horse race held annually in October since 1986 primarily at Laurel Park Racecourse in Laurel, Maryland or at Pimlico Race Course in Baltimore.  To be eligible for the Maryland Million Sprint Handicap, a horse must be sired by a stallion who stands in Maryland.  Due to that restriction the race is classified as a non-graded or "listed" stakes race and is not eligible for grading by the American Graded Stakes Committee.

Supporting paragraphs: National Stakes (SAJC) Morphettville Racecourse
Answer: 10