Which technique involves using different materials in an artwork?

The choice of mixed media is correct because this technique specifically refers to the incorporation of various materials into a single artwork. Artists using mixed media might combine traditional materials like paint and canvas with unconventional items such as fabric, paper, found objects, or even digital elements. This approach allows for greater creativity and expression as it challenges traditional boundaries and encourages experimentation with textures, forms, and artistic processes.

In contrast, realism is focused on depicting subjects as they appear in everyday life without idealization. Abstract expressionism emphasizes spontaneous and automatic artistic processes, often prioritizing emotion over representational accuracy. Impressionism, known for capturing the effects of light and movement, typically relies on singular forms of paint, usually oil on canvas, rather than combining different media. Thus, mixed media stands out as the definitive technique that utilizes a variety of materials in artwork.