Which of the following statements best describes the term command area ........

Geography Irrigation

Which of the following statements best describes the term command area?

Area served by a canal system through supply of water for irrigation.

Area of land, where the surface water from rainfall, snowmelt, or ice flow into a lower elevation to form a single body of water.

A unit of elevated land that separates waters flowing to different rivers, basins, or seas.

An area of land that contains a common set of streams and rivers that all drain into a single larger body of water.

Command area is the total area which can be economically irrigated from the irrigation system (canal system) without considering the limitation on the quantity of available water. Hence option (a) is the correct answer.
The command area is the area around the dam/project, where the area gets benefits from the dam, such as irrigation water, electricity, etc. It is an area which can be irrigated from a scheme and is fit for cultivation. In other words, it is the area around a dam which is under its command as an irrigation source.
It helps to build efficient farm water management practices for optimizing agricultural productivity and production and improving the socio-economic condition of farmers.
In 1974-75, the Government of India launched the Command Area Development programme to narrow the gap between irrigation potential created and actually utilized in major and medium irrigation schemes.
Hence option (a) is the correct answer.