The Four-Inch Course name was derived from regulations adopoted by a British private club which formerly owned what kind of company?
Four Inch Course: The Four-Inch Course was a road-racing circuit first used for the 1908 Tourist Trophy Race for cars, held on public roads closed for racing by an Act of Tynwald (the parliament of the Isle of Man). Four Inch Course:  The name of the course derives from the regulations for the 1908 Tourist Trophy adopted by the Royal Automobile Club, which limited the competitors' engines to a cylinder-diameter of four inches. Royal Automobile Club: The Royal Automobile Club is a British private club and is not to be confused with RAC, an automotive services company, which it formerly owned.
automotive services company