Final answer:
Millard Fuller likely performed Ceremonial Duties, such as public representation and speaking at events, after ending his service as president of Habitat for Humanity International.
Step-by-step explanation:
After Millard Fuller ended his service as president and transitioned to more of a figurehead role at Habitat for Humanity International, he most likely engaged in Ceremonial Duties. As a figurehead, Fuller would have been responsible for representing the organization and participating in events such as ribbon-cutting ceremonies or public speaking engagements. This typically includes activities such as speaking at events, representing the organization in a public capacity, and supporting fundraising efforts through his presence and prestige. Operational Management, Planning and Strategy, and Financial Analysis are generally roles that are more active and require day-to-day involvement, which would not align with a figurehead position.