Step 1: Understanding GDP sectors.
The GDP is contributed by three major sectors — Primary (agriculture, forestry, fishing, mining), Secondary (manufacturing, industries), and Tertiary (services).
Step 2: Contribution analysis.
In modern economies like India, the share of the primary sector (agriculture) has declined sharply compared to the secondary and tertiary sectors.
Step 3: Analyzing the options.
(A) Primary sector: Correct — least contribution in terms of GDP share.
(B) Secondary sector: Higher contribution than primary.
(C) Tertiary sector: Largest contributor to GDP.
(D) None of these: Incorrect.
Step 4: Conclusion.
The sector with the least contribution to GDP is the Primary sector.