Explanation:

- The Wholesale Price Index (WPI) is an important measure used in India to monitor the price change in wholesale markets.

- The base year is crucial for calculating the WPI, as it provides a reference point for price comparison.

- Option 3: 2011-12 is the correct answer. The base year for WPI calculation in India was updated to 2011-12 in 2015. This update was part of efforts to reflect more recent economic trends and production structures.

- Option 1: 2013-14, Option 2: 2014-15, and Option 4: 2012-13 are not correct as none of these years serve as the standardized base year for the WPI during 2019.

- Updating the base year periodically is essential to accommodate changes in consumption patterns, production techniques, and wider economic shifts.