You will hear a recording. Select the paragraph that best relates to the recording.

(1) The source of water and the money available dictate the techniques to be used for water purification, which can, therefore, not be uniformly applied.

(2) Water purification is neither a one-step or nor a one-rule process. The source, the contents, the standards and the cost-benefit parity will dictate the methods and stages of water purification.

(3)Seawater needs a different type of purification than does lake water, or, for that matter, any other source of water.

(4) Water purification has no quick-fix solution. It has to be based on the scientific studies about the quality of water, the source of water, the usage type and many other such factors.

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