Final answer:
The correct answer is option a) Synod of Carthage.
Step-by-step explanation:
The Synod of Carthage was responsible for declaring that only the twenty-seven canonical books of the New Testament were to be read in the churches. The Christian community's efforts to clarify and formalize the biblical canon life throughout the centuries, addressing various challenges to orthodoxy and doctrine.
During the period of ecumenical councils, the church leadership discussed myriad aspects of faith and worked toward establishing a unified Christian orthodoxy. Decisions made in these councils shaped the future of Christianity by determining the theological stances that would be regarded as orthodox, leading to the official recognition of the canonical books.
These councils played a critical role in the doctrine and practices of the Christianity and were convened by emperors to resolve matters of Christian doctrine within the Church. The issue of biblical canon, however, was concretely addressed in church synods like the one mentioned herein, rather than the larger ecumenical councils, which dealt with other theological disputes.