Use real-world metaphors” willmatch with the following UI designprinciple:(a) Directness (b) Efficiency(c) Familiarity (d) Flexibility

To match real-world metaphors with the UI design principles, we can analyze each option based on their characteristics:

1. Directness: This principle focuses on straightforward communication and interactions. Real-world metaphors help users understand the interface directly, making interactions intuitive. An example might be a trash can icon that represents deleting files.

2. Efficiency: This principle emphasizes minimizing the effort required to complete tasks. Real-world metaphors can streamline interactions, making them quicker. For instance, a folder icon representing file storage helps users efficiently manage their files.

3. Familiarity: This principle suggests using recognizable concepts to make the interface easier to use. Real-world metaphors rely on common items or experiences, making them familiar to users. An example is a shopping cart icon for online shopping.

4. Flexibility: This principle relates to the adaptability of an interface in various contexts. While real-world metaphors can sometimes enhance flexibility, they may not be as strong in this area as other principles.

Based on this analysis, the best match for "Use real-world metaphors" mainly aligns with: (c) Familiarity. This is because real-world metaphors rely on users' existing knowledge and experiences to create an intuitive user interface.