Step 1: Concept
The Human Development Index (HDI) is a composite index ranging from 0 to 1, where a value closer to 1 indicates a higher level of development.
Step 2: Meaning
The country "ranked the best" is the one with the highest numerical HDI value among the given choices.
Step 3: Analysis
• Looking at the table, Sweden holds the absolute highest HDI (0.952), but Sweden is not provided as an option.
• Comparing the options provided: Bhutan (0.681), Bulgaria (0.799), Mauritius (0.796), and Singapore (0.949).
• Singapore's score of 0.949 is significantly higher than the other three listed options.
Step 4: Conclusion
Out of the available choices, Singapore has the highest score and thus ranks the best.
Final Answer: (D)