Concept:The Eucharist is a Christian sacrament commemorating the Last Supper.Explanation:The term “Eucharist” comes from a Greek word meaning “thanksgiving,” but in Christian worship it specifically refers to the sacrament of the Holy Communion.It involves the consecration and sharing of bread and wine in remembrance of Jesus Christ.Therefore, the Eucharist is the Holy Communion, not just a prayer, sermon, or tithe.Answer:D. the Holy Communion