Final answer:
A) The Great Schism. The major debate concerning the atonement and the presence of Christ in the elements of communion happened during the Great Schism.
Step-by-step explanation:
The major debate concerning the atonement and the presence of Christ in the elements of communion occurred during the period of The Great Schism. The Great Schism, also known as the East-West Schism, took place in the 11th century and marked the separation of the Eastern Orthodox Church and the Roman Catholic Church. This division created significant theological differences between the two branches of Christianity, including disagreements about the nature of the Eucharist or communion.