Which of the following best defines the role of visual designers?

The role of visual designers is best defined by their responsibility for the aesthetic aspects of a product. Visual designers play a crucial part in shaping how a product looks and feels to users, which includes elements such as typography, color schemes, imagery, and overall layout. Their work is essential in ensuring that the visual presentation aligns with the brand identity and enhances the user experience. By focusing on these visual elements, they aim to create engaging and appealing interfaces that facilitate effective communication and usability for the end-users. This aligns with the broader goal of design, which is not only to make products functional but also visually attractive and consistent with the users' expectations and emotional responses.

The other roles do not accurately capture the primary focus of visual designers. For instance, developing technical functionality pertains more to software engineers and developers, while user research is more aligned with user experience (UX) researchers. Project management falls under the responsibilities of project managers, which is unrelated to the core competencies of visual design.