Who introduced the concept of virtual water?

The correct option is John Anthony Allan.

Explanation:

The concept of "virtual water" was introduced by Professor John Anthony Allan in 1993. Virtual water refers to the total volume of fresh water that is used to produce goods and services, particularly agricultural products. For example, it measures the water embedded in the production process of food, clothing, and other commodities from start to finish.

For his groundbreaking work in defining virtual water and demonstrating its impact on global trade, water management, and international relations, Tony Allan was awarded the Stockholm Water Prize in 2008.