How did lincoln’s ideas about slavery change?

question 4 options:

at first he willing to tolerate slavery in order to save the country, but then came to realize the country would need to permanently split up to stop the war.

at first he was willing to tolerate slavery in order to save the country, but then came to realize slavery had to end in order for the country to survive.

at first he wanted to end slavery, but then came to realize slavery had to continue in order for the country to survive.