Which term describes data elements that, when combined with other information, are used to single out an individual?

Data subjects refer to individuals whose personal data is being collected or processed. This term does not describe the data elements themselves but rather the people that the data pertains to. Thus, it does not fit the definition of data elements used to single out an individual.

Direct identifiers are specific pieces of information that can unequivocally identify an individual, such as a name or social security number. Unlike indirect identifiers, direct identifiers do not require additional information for identification, making this choice incorrect in the context of the question.

Personal details encompass a broad range of information about an individual and may include both direct and indirect identifiers. However, this term is too vague to specifically refer to the type of data elements that can be combined to single out an individual, which is precisely what indirect identifiers do.