Explanation:

- HDI value: The Human Development Index (HDI) is a composite indicator. It measures average achievement in three basic dimensions of human development: health, education, and income.

- Infant mortality rate: This indicates the number of infants dying before reaching one year of age, per 1,000 live births in a given year. It's vital for understanding a country's healthcare system.

- Liberty: This generally refers to individual freedoms and rights. It's a subjective and qualitative measure often not included in traditional quantitative development indices.

- All of the above: Suggests that multiple indicators could be excluded, but only liberty is usually missing from quantitative metrics.

Correct Answer: Option 3, Liberty