Step 1: Concept
Plants often modify their organs to store food or survive unfavorable conditions. These modifications can occur in roots, stems, or leaves.
Step 2: Meaning
Ginger is a perennial herb that grows horizontally under the soil surface.
Step 3: Analysis
Although it grows underground, ginger possesses nodes, internodes, and scale leaves, which are characteristic features of a stem rather than a root. Specifically, it is a modified underground stem known as a rhizome.
Step 4: Conclusion
Since the structure consumed is a rhizome, the edible part is botanically classified as a stem.
Final Answer: (C)