Which of the following conditions will result in the fastest transport through the xylem in a tree, assuming adequate water supply in the roots?

• A. Positive pressure potential in the xylem
• B. Positive pressure potential in the mesophyll
• C. Negative pressure potential in the guard cells
• D. Phloem transport being in the opposite direction from the xylem transport
• E. Negative pressure potential in the leaf mesophyll