The answer is b. the developer has expert knowledge of the device.
The developer's involvement with the device from the early stages implies that they possess in-depth knowledge and understanding of the device's design, functionality, and intricacies. This firsthand experience and expertise make the developer a strong and credible source of information for the instructional manual. They can provide accurate and detailed insights, answer technical questions, and offer valuable insights into the device's operation, maintenance, and best practices. Their expertise enhances the credibility and reliability of the information included in the manual.