What is the base year?

The correct option (or the base year itself) is:

2020

Explanation:

In macroeconomics, the base year serves as the benchmark year against which changes in prices and quantities are measured over time.

1. Given Baseline: The data explicitly states that the price and production for the year 2020 are used to calculate the initial GDP figure ($100 \text{ Kg} \times \text{Rs } 10 = \text{Rs } 1,000$).
2. Current Price Framework: When evaluating subsequent years (like 2021), economists compare the new market realities (Rs 15 per kg) against this established starting point to distinguish between nominal growth (due to inflation) and real growth (due to an increase in actual production output from 100 Kg to 110 Kg).