Final answer:
In the Christian practice of the Eucharist, believers drink wine to remember the blood of Jesus, as instituted by Christ at the Last Supper. The act is a core element of Holy Communion and varies in interpretation among different Christian denominations.
Step-by-step explanation:
Christians participating in the Eucharist would primarily drink wine in remembrance of the blood of Jesus. This practice was initiated by Christ himself during the Last Supper, as narrated in the Bible, where Christ blessed the bread and wine and shared it with his apostles, saying 'Take, eat; this is my body' and 'Drink from it all of you; for this is my blood of the covenant, which is poured out for the forgiveness of sins' (Matthew 26). While the exact understanding of the Eucharist varies among different denominations, with Catholics and Eastern Orthodox believing in the literal transformation known as transubstantiation, and Protestants viewing it as a symbolic reminder of Christ's sacrifice, the central elements of bread and wine are universal in the Christian practice of Holy Communion. The other options presented, such as eating bitter herbs, reading the Shema, or leaving a seat open for the return of Elijah, are not associated with the Christian Eucharist but rather with other religious traditions or rituals.