The answer would depend on the specific lesson you are referring to. However, if you need to choose one option that is often highlighted in various lessons regarding significant social movements, all of the listed options—Transcendentalism, Abolition, Women's suffrage, and Education reform—are important and transformative movements in American history.
If you have a particular context or information about the lesson in question, please provide that, and I can assist you in choosing the most relevant option!