Market researchers sent an opinion survey to every twenty-fifth person who ordered a subscription to a weekly news magazine. the researchers were most clearly employing a technique known as:

random sampling

Explanation:

Random sampling -

As can be determined from the word , the sampling which is done on the random fashion , is random sampling.

It is the method , by which some samples are distributed to certain random people or object from a group of people or object , is referred to as random sampling.

It is also known as probability sampling.

Hence ,from the given scenario of the question ,

The correct term is random sampling.

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