Which statement best describes single-tier computing?

The statement that describes single-tier computing as "data, business logic, and presentation are all combined into one application or database" accurately reflects the essence of single-tier architecture. In a single-tier system, all elements of the application—namely the data storage, the processing of business logic, and the user interface—are housed within a single environment or software application. This integration means that the application can manage everything from handling user inputs to storing and retrieving data without the need for interaction with separate, distinct systems or layers.

This architecture is beneficial for smaller applications or environments where simplicity and low overhead are desired, such as local applications on a desktop. In contrast, the other options discuss multi-tier or distributed architectures, where functionalities are split across multiple applications or servers, which is not characteristic of single-tier systems. By centralizing everything into one application, single-tier computing simplifies development and deployment but can limit scalability and flexibility compared to more complex architectures.