Data is typically classified into two main types: structured and unstructured.

Structured data is highly organized, formatted for a predefined data model, and easily searchable in tabular form (e.g., columns and rows in a database, like customer names, order IDs, or star ratings).

Unstructured data lacks a pre-defined format or organization.

The customer feedback described is a detailed, free-text response written in the customer's own words. This qualitative data, whether it is an email, an essay, or a long-form survey response, does not fit into fixed fields and requires advanced Natural Language Processing (NLP) or Generative AI techniques to extract meaning. Since the text is non-tabular and has no inherent structure enforced by the collection method, it is correctly classified as Unstructured Data.

Quantitative data (D) refers to numerical values that can be counted or measured. Labeled data (C) is data that has been tagged with a meaningful output category, which this raw feedback has not yet received.

(Reference: Google's Generative AI Study Guides define Unstructured Data as data that does not have a predefined structure or data model, such as text documents, images, audio, and video. Free-text responses in a survey are a primary example of unstructured data.)