Which of the following best describes the responsibilities defined within a PSC?

The responsibilities defined within a Publication Steering Committee (PSC) primarily include outlining roles and responsibilities at the project's outset. This is critical for ensuring clarity among all stakeholders regarding who is accountable for different aspects of the publication process. By establishing these roles early, the PSC helps to facilitate collaboration and streamline the workflow, ensuring that all contributors understand their specific duties and contributions to the project.

This proactive approach is vital as it sets the foundation for effective communication, decision-making, and accountability throughout the publication cycle. The PSC typically consists of representatives from various disciplines involved in publication, making it an integral component in aligning the publication's goals with the expectations of stakeholders.

The other options do not accurately reflect the core responsibilities of a PSC. For example, communicating with external stakeholders is important but is not the primary focus of a PSC. Similarly, developing a comprehensive marketing strategy and compiling a list of potential co-authors may be tasks relevant to a broader project context but do not pertain specifically to the PSC's main responsibilities. Thus, outlining roles and responsibilities stands out as the correct definition of what a PSC is intended to achieve.