The correct answer is Option 3: 1, 2, and 3.

The International Food Policy Research Institute (IFPRI) computes the Global Hunger Index (GHI) Report to measure and track hunger worldwide. The GHI is calculated using four indicators, including:

1. Undernourishment: This indicator measures the proportion of the population that is undernourished and reflects the share of the population with insufficient caloric intake.

2. Child stunting: This indicator measures the percentage of children under five years old who have low height for their age. Stunting is an indicator of chronic undernutrition and reflects long-term insufficient nutrient intake.

3. Child mortality: This indicator measures the mortality rate of children under five years old. High child mortality rates are a sign of poor child health and inadequate access to healthcare.

4. Child wasting: This indicator measures the percentage of children under five years old who have low weight for their height. Wasting is an indicator of acute malnutrition and reflects recent inadequate nutrient intake.

IFPRI uses a weighted average of these four indicators to calculate the GHI. The weights for each indicator are as follows: Undernourishment (50%), Child stunting (30%), Child mortality (10%), and Child wasting (10%). Therefore, options 1, 2, and 3 are correct since all three indicators are used by IFPRI to compute the GHI.

The GHI is a useful tool for policymakers and development practitioners to monitor progress in reducing hunger and to prioritize interventions to improve food security and nutrition.