Concept:Idul-Ad-ha (Eid-ul-Adha) emphasizes obedience, sacrifice, and generosity.Explanation:The festival commemorates Prophet Ibrahim’s willingness to sacrifice his son in obedience to God. It also teaches sharing with the needy and showing generosity. Therefore, an activity that explains and promotes obedience, sacrifice, and generosity best reflects the key value of Idul-Ad-ha.Answer:D. Organizing a seminar on obedience, sacrifice and generosity