What is the key characteristic of random sampling?

The key characteristic of random sampling is that every individual has an equal chance of being selected. This method is fundamental in research as it ensures the sample is representative of the larger population, minimizing selection bias. By giving each member of the population an equal probability of being included in the sample, researchers can confidently generalize their findings to the broader group. Random sampling enhances the validity of research results, allowing for statistical analyses that assume the randomness of the sample, which is crucial for drawing reliable conclusions.

Other methods, such as selecting respondents based on availability or specifying quotas based on certain characteristics, introduce bias and limit the representativeness of the sample. Similarly, systematic sampling methods, which involve selecting every nth individual, while random, differ in their strict adherence to equal probability for every individual that random sampling imposes. Thus, option A accurately captures the essence of random sampling.