The correct answer is Option 3 (Only d). Explanation & Key Takeaways: • The Consumer Price Index for Industrial Workers (CPI-IW) is used to measure the changes in the cost of living for industrial workers in India. • The index helps policymakers determine dearness allowance (DA) and other benefits for industrial workers, ensuring fair wages and a decent standard of living. • The CPI-IW is based on a fixed basket of goods and services that are periodically revised to reflect changing consumption patterns. • The index is also used in wage agreements, pension calculations, and policy decisions to ensure that workers' real income levels are maintained despite inflation. Important Notes: • The CPI-IW is compiled and published by the Labour Bureau, an attached office of the Ministry of Labour and Employment, Government of India. • The index is calculated for different industrial centers across the country to ensure regional representation and accuracy. • The base year for the CPI-IW is periodically revised to ensure that the index reflects current economic realities. • It covers a wide range of goods and services, including food, housing, clothing, education, medical expenses, and more.