Which of the following is a full-scale working model used to test design concepts?

A full-scale working model used to test design concepts is known as a prototype. Prototypes serve as tangible representations of ideas and allow designers and engineers to explore the functionality and usability of the design before final production. They can be built using various materials and techniques, and they help identify potential issues early in the design process, facilitating necessary adjustments.

In contrast, a mockup typically refers to a model that exhibits the appearance of a product but may not include functionality. Illustrations and samples are often used to convey ideas or demonstrate capabilities but do not function as working models to test concepts directly in a practical environment. Therefore, the prototype is distinguished by its ability to simulate the performance of the final product, making it essential for testing and validating design ideas.