Full Detailed in Depth Explanation:

Oracle HCM Cloud allows assigning responsibilities to individuals for specific tasks or groups, such as a Fitness Representative for a fitness program. The setup should leverage existing functionality efficiently.

Option D ("Define the person's area of responsibility to reflect Fitness Representative") is correct. In Oracle HCM, "Areas of Responsibility" (AOR) can be defined via the "Manage Areas of Responsibility" task to assign specific duties (e.g., Fitness Representative) to a person for a group of workers. This is a standard feature for designating responsibilities without requiring new jobs or flexfields, as outlined in the "Implementing Global Human Resources" guide.

Option A ("Deploy a Key Flexfield to capture the information") is incorrect. Key Flexfields (KFFs) are used for structured data (e.g., job codes), not responsibilities.

Option B ("Deploy a Descriptive Flexfield to capture the information") could work for custom attributes but is overkill when AOR is available.

Option C ("Create a new job Fitness Representative and associate that to the person") is unnecessary; a job defines a role, not a specific responsibility for a program.