Explanation:

- The National Development Council (NDC) was established to strengthen and mobilize the effort and resources of the nation in support of the plan.

- Option 1: 1950: This year marks the formation of the Planning Commission of India, not the NDC.

- Option 2: 1969: This year does not correspond to any formation related to the NDC.

- Option 3: 1952: The NDC was actually set up in 1952 as an adjunct to the Planning Commission to ensure cooperation among various governments in India and the implementation of national plans.

- Option 4: 1979: Not related to the establishment of the NDC or Planning Commission.