A doughnut shop has a special on its Mix-n-Match selection, which allows customers to select three doughnuts from the following varieties: frosted, apple cider, maple, Boston creme, plain, peanut butter, and chocolate. How many different Mix-n-Match selections are possible?[Hint: Consider when all three doughnuts are the same, two are the same, and none are the same.]There are possible selections.(Type a whole number.)