The correct answer is: c) Lower than the national average.
Arunachal Pradesh’s HDI score is 0.631, which is lower than the national average of 0.647. This means that Arunachal Pradesh is a developing state with a medium human development index.
The HDI is a composite index of three indicators: life expectancy at birth, mean years of schooling, and expected years of schooling, adjusted for educational attainment. It is used to measure the average achievement in a country in terms of health, education, and standard of living.
Arunachal Pradesh has a high life expectancy at birth, but its mean years of schooling and expected years of schooling are lower than the national average. This suggests that the state has made progress in improving health outcomes, but it still has work to do in terms of education.
The HDI is a useful tool for comparing the development of different countries and regions. It can also be used to track progress over time. However, it is important to note that the HDI is just one measure of development. It does not take into account other important factors, such as inequality, poverty, and environmental sustainability.