When a plant is not strong enough to support its own weight?

Answer:
The correct answer will be option-B
Explanation:
The plant cell contains an additional layer around the plasma membrane called cell wall which is composed of the cellulose (polysaccharide), hemicellulose, pectin and other proteins in a small amount.
This cell wall protects the cell as well as provides mechanical strength to the cell and as a whole to the plant. If a plant is not able to stand straight or is not able to support its own weight indicated that the plant lacks these cell wall components majorly cellulose.
Thus, Option-B is the correct answer.