Water balance approach was given by

Answer: Option B

The water balance approach was given by Thornwhite.
The law of water balance states that the inflows to any water system or area are equal to its outflows plus the change in storage during a time interval.
In hydrology, a water balance equation can be used to describe the flow of water in and out of a system. It can also be referred to as how an organism maintains water in dry or hot conditions.