Step 1: Concept
Hard gelatin capsules are available in standardized sizes ranging from 000 to 5.
Step 2: Meaning
The numbering system follows an inverse relationship: as the numerical value of the size increases, the physical capacity and dimensions of the capsule decrease.
Step 3: Analysis
Size 000 is the largest (approx. 1.37 ml), followed by 00, 0, 1, 2, 3, 4, and finally 5. Size 5 has the smallest volume (approx. 0.13 ml).
Step 4: Conclusion
Among the options provided, 5 represents the smallest capsule size.
Final Answer: (D)