Which of the following options is necessary to make HDI a complete and a better indicator? 

Liberty indicators

The correct answer is Option 2: Liberty indicators

All the components of HDI are extremely important indicators; but these are not sufficient. Along with these, we also need what may be called ‘liberty indicators’. It can include- the extent of Constitutional protection given to rights of citizens or the extent of constitutional protection of the Independence of the Judiciary and the Rule of Law. One such indicator has actually been added as a measure of ‘the extent of democratic participation in social and political decision-making’ but it has not been given any extra weight.