Final answer:
Abigail Adams is buried at First Unitarian Church in Quincy, Massachusetts.
Step-by-step explanation:
Abigail Adams is buried at First Unitarian Church in Quincy, Massachusetts. According to the given information, Abigail Adams is best remembered for her letters to her husband, John Adams, who later became the second president of the United States. The answer choice c) First Unitarian Church, Quincy, Massachusetts matches the location where Abigail Adams is buried.