The correct answer is (b).
The new Wholesale Price Index (WPI) series was introduced on 1 July 2010. The new series is based on the 2011-12 base year, replacing the earlier series based on the 1993-94 base year. The new series is designed to be more representative of the current structure of the Indian economy and to provide a better measure of inflation.
The new WPI series is compiled using a modified Laspeyres formula. The weights for the new series are based on the 2011-12 input-output table. The new series also includes a number of new items, such as services, which were not included in the earlier series.
The new WPI series is released on a monthly basis. The data is released by the Ministry of Commerce and Industry, Government of India.
The following are the options for the question:
(a) 1 April. 2010: This is incorrect. The new WPI series was introduced on 1 July 2010, not 1 April 2010.
(b) 1 July, 2010: This is the correct answer. The new WPI series was introduced on 1 July 2010.
(c) 15 August, 2010: This is incorrect. The new WPI series was introduced on 1 July 2010, not 15 August 2010.
(d) 14 September, 2010: This is incorrect. The new WPI series was introduced on 1 July 2010, not 14 September 2010.