Sand and gravel operators

Sand and gravel operators 1A: “Sand and gravel operators in Sault Ste. Marie, Ontario sell most, if not all, of their products within the Sault Ste. Marie area. Why should they not use trucks to haul their products to southern Ontario where prices could be higher?”            12 marks 1B: What conditions are likely to make it possible for sand and gravel products from the Sault Ste. Marie region to be sold routinely in the Southern Ontario market?