A celery stalk was placed into a beaker of blue dye. When the dye reached the leaves, the stalk was taken out and a section was cut, as shown in the diagram.

Which diagram shows the appearance of the cut end of the stalk?

The dissolved blue dye moves like water through the conducting elements of plants (i.e., xylem tubes) into the celery stalk and leaves.
Option A is not correct as it does not show presence/movement of dye.
In option C, the outlined portion of the cut end of stalk is shown colored, indicating the movement of dye , but the movement of dye takes place through xylem which is located towards the inner side. Hence option C is also incorrect.
Option D shows the movement of dye through entire region of stalk region which is again not correct.
Therefore the correct option is B, as it precisely shows the movement of dye through xylem. In a mature plant xylem is stacked end to end in the center of the plant, forming a vertical column that conducts water and minerals absorbed by the roots upward through the stem to the leaves.