In His Freeport Doctrine, Douglas Defended Popular Sovereignty Despite the Dred

In his Freeport Doctrine, Douglas defended popular sovereignty despite the Dred Scott ruling by arguing that

A) the Scott case was not a valid constitutional interpretation.
B) if the people of a territory refused to pass a slave code, slavery would never be established there.
C) Americans would stand behind congressional legislation to reverse the decision.
D) strategic river cities that chose to ban slavery within their city limits would set the tone for the whole territory.