A language model is used to generate potential summaries for a long document. The model produces 5 different summaries for consideration. If this collection of summaries is treated as a set of candidate solutions, which expression below correctly represents this specific set?

Given the formal representation of a set of potential solutions, $\mathcal{D}_c = \{\mathbf{y}_1, ..., \mathbf{y}_K\}$, match each symbol to its correct description.

Representing a Set of Generated Textual Responses