Answer:
Your sister.
Step-by-step explanation:
4 liters ≈ 4.22675284 quarts.
If your sister drank 4 quarts of water, then she would have drank more because 4 > 3.
I multiplied 4 by 1.06 and got 4.22675284 [ Rounded ], which is how much quarts your sister drank.