Please choose the correct solution to the question: How to make home-made butter.

Solution1: Fill heavy cream half way full into a jar. Screw the lid and make sure it is tight. Shakes well for about 10 minutes. Once it turns solid, it is butter.

Solution2: Fill milk half way full into a jar. Screw the lid and make sure it is tight. Shakes well for about 10 minutes. Once it turns solid, it is butter.

Answer format: solution1/solution2
Answer: solution1