Step 1: Understanding the Concept:
This question pertains to the economic history of India, specifically the focus of its Five-Year Plans for development.
Step 2: Detailed Explanation:
India adopted the model of five-year plans to guide its economic development after independence.
First Five-Year Plan (1951-1956): The primary focus was on the agricultural sector, including investments in dams and irrigation to overcome food shortages.
Second Five-Year Plan (1956-1961): This plan was based on the P.C. Mahalanobis model. The focus shifted from agriculture to rapid industrialization, with a special emphasis on the development of heavy industries and capital goods. This was done to build a strong industrial base for the country.
Therefore, the main focus of the second plan was Industry.
Step 3: Final Answer:
The main focus of the Second Five-Year-Plan was rapid industrialization, particularly heavy industries.
Thus, option (C) is correct.