Preheat the oven to 400°F. Lightly grease a baking sheet, or line it with parchment., In a large bowl, stir together the flour, sugar, salt, baking soda and baking powder., Make a well in the dry ingredients and pour in the buttermilk and the oil or butter. Stir together until blended — some lumps will remain., Turn the dough out onto a floured board and knead about 10 times, or until it all holds together., Form the dough into a large ball and place it on the prepared baking sheet. Cut a deep cross in the top., Bake the bread for approximately 40 minutes, or until it tests done (a cake tester or toothpick inserted into the center will come out clean)., Remove the bread from the oven, and cool it on a rack. Enjoy warm or at room temperature. Serve with sweet butter and a dollop of marmalade, if desired., Store, well-wrapped, for a couple of days at room temperature; freeze for longer storage.