Which sector's share in GDP increased significantly by 1990, reflecting a shift in the Indian economy?

The correct option is Industry.

Explanation and Background:

In the post-independence period up to 1990, the Indian economy underwent significant structural changes. At the time of independence, agriculture was the dominant sector, contributing the largest share to India's Gross Domestic Product (GDP).

Through systematic economic planning and industrialization policies (such as the Five-Year Plans), the share of the industrial sector in GDP increased substantially by 1990. While agriculture's relative contribution to GDP declined over the decades, the industrial sector (along with the services sector in later years) expanded significantly, reflecting a major structural transition in the Indian economy.