Objective: how to make icing

Which of the following solutions is more sound in terms of naive physics reasoning?

Pick your answer from: --3 cups powder sugar 1/3 cup butter, softened 1 1/2 teaspoons vanilla 1 to 2 tablespoons milk In medium bowl, mix powdered sugar and butter with spoon or electric mixer on low speed. Stir in vanilla and 1 tablespoon of the milk. Gradually beat in just enough remaining milk to make frosting smooth and spreadable. If frosting is too thick, beat in more milk, a few drops at a time.. --3 cups granulated sugar 1/3 cup butter, softened 1 1/2 teaspoons vanilla 1 to 2 tablespoons milk In medium bowl, mix powdered sugar and butter with spoon or electric mixer on low speed. Stir in vanilla and 1 tablespoon of the milk. Gradually beat in just enough remaining milk to make frosting smooth and spreadable. If frosting is too thick, beat in more milk, a few drops at a time..
3 cups powder sugar 1/3 cup butter, softened 1 1/2 teaspoons vanilla 1 to 2 tablespoons milk In medium bowl, mix powdered sugar and butter with spoon or electric mixer on low speed. Stir in vanilla and 1 tablespoon of the milk. Gradually beat in just enough remaining milk to make frosting smooth and spreadable. If frosting is too thick, beat in more milk, a few drops at a time.