An example of an external integration tool would be to:

Including user representatives as active members of the project team is an example of an external integration tool because it enhances collaboration and communication between the project team and the users who will ultimately utilize the product or service being developed. This approach helps ensure that the needs and requirements of the users are accurately captured and addressed throughout the project lifecycle, facilitating alignment between project goals and user expectations.

By involving user representatives directly in the project team, the project can benefit from their insights and feedback, which can lead to a more successful outcome. This type of integration allows for real-time adjustments based on user input, fostering a more user-centered design and development process.

The other options, while important aspects of project management, focus more on internal processes and planning rather than integration with external stakeholders. Task dependencies and PERT charts are tools for managing and visualizing project timelines and workflows, and frequent team meetings primarily serve to enhance communication among internal team members rather than bridging the gap with outside users. All these elements are crucial, but they primarily operate within the project team instead of facilitating external integration.