Detailed Explanation:

The process owner is accountable for the long-term maintenance and sustainment of improvements post-implementation.

Option B: Process Owner

This roleensures continuous oversight and improvement adherence, critical for sustaining changes.

Option A: Champion

Champions advocate and promote the initiative but may not manage ongoing maintenance.

Options C and D:

Sponsors provide support, and facilitators assist in the project’s implementation but do not hold responsibility for sustainment.