Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are
A) hypertonic to both freshwater and the salt solution.
B) hypotonic to both freshwater and the salt solution.
C) hypertonic to freshwater but hypotonic to the salt solution.
D) hypotonic to freshwater but hypertonic to the salt solution.
E) isotonic with freshwater but hypotonic to the salt solution.