Which set of ordered pairs is not a function? A)(2, 3),(4,9), (3, 8), (4, 15)
B) (-9, 4), (-6, 3), (-2, 8), (0, 21)
C) (1, 2), (3,5), (6,9), (7, 11)​

Answer asap and if you do you will get brainliest. catherine buys a gallon of ice cream from the store. after taking it home, she eats a fifth of a gallon of ice cream. her sister eats some of the ice cream as well. if two-thirds of the original amount of ice cream is left, then what fraction of a gallon of ice cream did her sister eat?