What advantages did using the elodea stalk have over using its leaf or leaves?

While conducting an experiment, when one is trying to witness the procedures of plasmolysis, the stalk is better suited. As one is able to expose the more underlying tissue to the solution of the salt and the process is much faster to visualize and at the same time, it replicates the natural position of a more realistic outcome than when leaves or leaf are used.  

Plasmolysis refers to the procedure where the plants gain water in a hypotonic solution and lose water in a hypertonic solution because of osmosis. This leads to the protoplasm, as osmosis refers to a phenomenon, which needs no energy of the cell and cannot be monitored, thus, cells cannot prevent plasmolysis from occurring.  

the correct answer is b