To accurately respond to your question, I would need to know which video you are referring to. However, historically, John Adams played a significant role in the Boston Massacre as he represented the British soldiers in their trial, advocating for justice and fair treatment.
If you need information about his role in the Boston Tea Party, the Battle of Bunker Hill, or the Constitutional Convention, please provide more context. Based on the typical knowledge of Adams' contributions, the answer would likely be:
B. Boston Massacre
Please verify this with the content of the specific video for accuracy.