CREATE TABLE table_14001 ("City" TEXT, "System" TEXT, "Category" TEXT, "Daily ridership" FLOAT, "As of" TEXT, "Opened" FLOAT, "Stations" TEXT)

Which category has 5 stations?
SELECT "Category" FROM table_14001 WHERE "Stations" = '5'
SELECT "Category" FROM "table_14001" WHERE "Stations" = '5'