Correct Option
Statement 2 is correct. The Secretary of the Planning Commission of India also served as the ex-officio Secretary of the National Development Council (NDC). The NDC was the apex inter-governmental body responsible for approving Five Year Plans and reviewing their progress.
Statement 3 is correct. The Constitution of India includes "Economic and social planning" in Entry 20 of the Concurrent List (List III) in the Seventh Schedule. This constitutional provision enables both the Parliament and the State Legislatures to enact laws on matters related to economic and social planning.
Incorrect Options
Statement 1 is incorrect. The Planning Commission was an advisory body responsible for formulating Five Year Plans. However, the highest decision-making authority for the approval of these plans rested with the National Development Council (NDC), which comprised the Prime Minister, Union Cabinet Ministers, Chief Ministers of all States, and Administrators of Union Territories. Parliament also played a crucial role in approving the financial allocations and legislative frameworks for these plans. Therefore, the Planning Commission was not the highest deciding body.
Option (a) is incorrect because Statement 1 is incorrect.
Option (c) is incorrect because while Statement 2 is correct, Statement 3 is also correct, making this option incomplete.
Option (d) is incorrect because while Statement 3 is correct, Statement 2 is also correct, making this option incomplete.