<human>: Objective: How can you extend freshness in cut flowers?

Which of the following solutions is more sound in terms of naive physics reasoning?

OPTIONS:
- Add 1/2 cup buttermilk to an almost full vase of cold water, insert your flowers, this will preserve the flowers.
- Add 1/2 cup of 7 up to an almost full vase of cold water, insert your flowers, this will preserve the flowers.
<bot>: Add 1/2 cup of 7 up to an almost full vase of cold water, insert your flowers, this will preserve the flowers.