Step 1: Understanding the Question:
This question tests knowledge of medicinal plants.
Step 2: Detailed Explanation:
Panax ginseng is known as a "cure-all" and is used for treating various diseases.
It is highly valued in traditional medicine.
Hedychium spicatum (A): Used for specific ailments.
Gymnema sylvestre (B): Used for diabetes.
Gloriosa superba (D): Used for gout and rheumatism.
Thus, the correct answer is Panax ginseng.
Step 3: Final Answer:
Thus, Panax ginseng is known for treating many diseases, which corresponds to option (C).
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