Which of the following is a duty engineers must perform in their role?

In the context of the duties of engineers, acting independently of the owner is crucial for upholding professional ethics and integrity in their role. Engineers are expected to provide honest, objective assessments and recommendations that are in the best interest of public safety and welfare, not just aligned with the owner's desires or financial pressures. This independence allows engineers to stand firm on their professional judgment, ensuring that decisions made during the project are based on technical merit and adherence to relevant codes, standards, and regulations. Upholding this independence is essential to maintain the engineering profession's trustworthiness and credibility.

The other options involve responsibilities that can be influenced by external factors, such as cost reduction, which may not always align with ethical engineering practice, or delegating inspections, which could compromise quality assurance if not supervised properly. Predicting market trends falls outside the core responsibilities of engineers, as their primary focus is typically the design, safety, and functionality of engineering projects.