The correct answer is D. both (a) and (c).
Department representatives on a feasibility committee serve as a ready source of information about their departments and as direct users of the new system. They can provide valuable information about the needs of their departments and how the new system can meet those needs. They can also provide feedback on the usability and functionality of the new system.
Option A is correct because department representatives are a ready source of information about their departments. They know the current processes and procedures, the challenges that their departments face, and the needs of their employees. This information is essential for developing a new system that will be successful.
Option C is also correct because department representatives are direct users of the new system. They will be using the system to do their jobs, so they need to be involved in the development process to ensure that the system meets their needs. They can also provide feedback on the usability and functionality of the new system.
Option B is not correct because department representatives are not liaisons to their departments. They are representatives of their departments, but they are not responsible for communicating with their departments about the new system. This is the responsibility of the project manager or another member of the feasibility committee.
Option E is not correct because both options A and C are correct.