Final answer:
The altar in a Christian church symbolizes the Table of the Last Supper of Christ, the tombs of Christ and the saints, and serves as the church's focal point. Thus, the correct answer is 'c. Both a and b'.
Step-by-step explanation:
An altar in a Christian church symbolizes multiple aspects of the faith, primarily functioning as a representation of the Table of the Last Supper of Christ as well as memorializing the tombs of Christ and the saints. In the religious practice of Christianity, particularly within the context of a church, the altar is a sacred space where the Eucharist is celebrated. This ritual is a direct reference to the Last Supper, where Jesus Christ shared bread and wine with his apostles, symbolizing his body and blood. The altar is also reminiscent of the early Christian practice of celebrating the Eucharist over the tombs of martyrs and saints, connecting the physical church with the celestial church.