Final answer:
The statement not true of the Abolitionist Movement is that they only wanted to stop the spread of slavery out West; instead, they aimed for its complete abolition through moral suasion and activism.
Step-by-step explanation:
In the context of the early 1800s Abolitionist Movement, not all members sought to only prevent the spread of slavery westward. Abolitionists like William Lloyd Garrison pushed for the immediate and unconditional end of slavery, and their movement was not confined to limiting slavery's expansion.
They emphasized moral suasion in their advocacy, establishing various societies and utilizing mass communication to educate the public about the evils of slavery and ultimately achieve its eradication. The statement C, 'They only wanted to stop the spread of slavery out West,' is therefore not true of the members of the Abolitionist Movement as they aimed for a complete abolition of the institution.