In Which of the Situations Below Would a Plant Be

Multiple Choice

In which of the situations below would a plant be at greatest risk for the formation of air bubbles in the xylem stream?

A) in the early morning, with cooler temperatures and calm winds
B) only on a day during a drought
C) The risk is the same at any time of day.
D) during the afternoon, when transpiration is highest
E) during the night, when transpiration is low