The most acceptable inference about a plant that is not getting any water is:
D. The plant will die unless it gets water.
This is because all plants require water to survive, and a lack of water will ultimately lead to the plant's death unless it has specific adaptations to cope with drought. Options A, B, and C are not necessarily true for all plants; for example, not all plants need better soil, not all are cacti, and not all have adaptations for storing water.