Step 1: Concept
Plant gums are dried exudates obtained from the stems or branches of specific botanical species.
Step 2: Meaning
Tragacanth is a natural gum used as a thickening agent and stabilizer in pharmacy.
Step 3: Analysis
Acacia is obtained from Acacia senegal, while Tragacanth is the dried gummy exudate from Astragalus gummifer or other species of Astragalus.
Step 4: Conclusion
Astragalus gummifer is the botanical source for Gum Tragacanth.
Final Answer: (C)