Answer:
B. Even though we have different reasons, we all basically agree that Christopher Marlowe couldn't have written Shakespeare's plays.
Step-by-step explanation:
In a group discussion, the best example of synthesizing claims into a single conclusion is "even though we have different reasons, we all basically agree that Christopher Marlowe couldn't have written Shakespeare's plays."
Group discussions help people to gather different information and opinions that will make it complete. But such discussions becomes meaningful when everyone comes to an agreeable conclusion despite the different viewpoints.
Therefore, agreeing that Christopher Marlowe couldn't have written Shakespeare's plays despite the different reasons people had, is a proper way of synthesizing claims into a single conclusion.