Which of the following best defines the purpose of the Digit Span subtest?

The purpose of the Digit Span subtest is best defined as assessing short-term and working memory. This specific subtest involves the presentation of a series of digits that the participant must repeat back in the same order (forward recall) or in reverse order (backward recall). The ability to successfully repeat these digits demonstrates a person's capacity to temporarily hold and manipulate information in their mind, which are key components of both short-term and working memory.

While other options touch on different cognitive skills, they do not accurately represent the specific focus of the Digit Span task. For example, evaluating a person's mathematical skills isn’t part of the subtest's objectives, as it doesn't involve numerical calculations or problem-solving. Similarly, the task does not assess social communication abilities, nor does it aim to gauge overall intelligence comprehensively, as it specifically targets memory capabilities rather than providing a general measure of cognitive functioning. Thus, the correct choice emphasizes the role of the Digit Span subtest in understanding aspects of memory rather than broader cognitive or social abilities.