The ITIL 4 guiding principle 'collaborate and promote visibility' emphasizes working together and making work visible to all relevant stakeholders. When improving a service desk practice, this principle ensures that agents understand the broader business context and maintain good communication with other teams.

Collaboration: Encourages working across teams to ensure that information flows efficiently between departments. This would be especially beneficial for service desk agents, as they frequently interact with various parts of the organization.

Visibility: Promotes making key work, challenges, and activities visible to stakeholders to enhance decision-making and problem-solving.

In this context, Option D ('Include business tours in induction training for service desk agents') fits best because it helps new agents understand the business's environment, promotes visibility into how the service desk contributes to the organization, and facilitates better collaboration with other teams.

Incorrect Options:

Option A: Using existing procedures doesn't emphasize collaboration or visibility.

Option B: Automating processes can improve efficiency but is more aligned with the 'optimize and automate' principle.

Option C: Creating familiar interfaces relates more to usability, not collaboration.