Final answer:
The correct answer is 'c. design review meetings,' which mark a critical point in the design process where stakeholders review a project's preliminary design and work towards consensus before further development.
Step-by-step explanation:
The correct answer to the question is 'c. design review meetings.' A preliminary design review meeting happens when the contractor has completed the initial conceptual specifications, drawings, or flowcharts. The purpose of this meeting is to obtain the customer's agreement on the proposed design, showing how it meets the criteria and constraints established in earlier phases. The process involves refining the design, developing a detailed design, and potentially selecting a different concept if the original does not work, which is characteristic of a spiral design process. This meeting is essential as it allows for a comprehensive review and ensures that all parties are aligned before moving forward. Following the review and agreement, each designer can progress with the finer details of the project, moving from sketches to detailed drawings, and eventually to the construction of the design.