JEE Main 2019 Chemistry question

The freezing point of a diluted milk sample is found to be −0.2°C, while it should have been −0.5°C for pure milk. How much water has been added to pure milk to make the diluted sample?

• (A)1 cup of water to 2 cups of pure milk
• (B)2 cups of water to 3 cups of pure milk
• (C)3 cups of water to 2 cups of pure milkCorrect
• (D)1 cup of water to 3 cups of pure milk