The correct option is D cusecs
During flood, water level in the rivers rise, which leads to a rise in the water level in reservoirs. To maintain a safe water level, a large volume of water released from the reservoirs.
Cusecs (cubic centimetres per second) is a unit used to measure the amount of water released from the reservoirs. However, gallons, litres and millilitres are units used to measure the volume of liquids.