The correct answer is B) A Senator.
Both men were trying to be a Senator from the state of Illinois. The Lincoln-Douglas debates became widely popular due to the civility and depth of the arguments made by both men. The topics discussed during these debates varied but mainly focused on the issue of slavery as an institution. The debate was not about the morality of slavery, rather it was about the existence of this institution within different cities in Illinois. This is where the Freeport Doctrine would be developed by Douglas.