Please choose the correct solution to the question: How to make frosting.

Solution1: In medium bowl, mix powdered sugar and water 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.

Solution2: 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.

Answer format: solution1/solution2
Answer: solution2