Final answer:
Heresy in the church causes controversy due to opposing beliefs in religious theories, leading to doubt, unbelief, and changes in thought. Same belief systems do not cause issues in the church.
Step-by-step explanation:
Heresy in the church causes controversy due to opposing beliefs in religious theories, which can result in doubt and unbelief (option A). When individuals or groups within the church hold beliefs that go against the established teachings, it challenges the authority and unity of the church. These opposing beliefs can also lead to changes in eventual thought and the formation of different sects or denominations (option C). Same belief systems do not cause issues in the church because they align with the established teachings and do not challenge the status quo (option D).