The average surface area of a reservoir in the month of June is 20 km2. In the same month, the average rate of inflow is 10 m3/s, outflow rate is 15 m3/s, monthly rainfall is 10 cm, monthly seepage loss is 1.8 cm and the storage change is 16 million m3. The evaporation (in cm) in that month is:
1
46.8
2
136.0
3
13.6
4
23.4