Based on the map and the implications of the Missouri Compromise, the most appropriate response would be:
There was more territory north of the line.
This response highlights the fact that the compromise allowed for more free land to be available north of the 36°30' parallel, which could be seen as providing the Northern states with more opportunity for settlement and economic development compared to the Southern states. This would likely lead some Southerners to feel that the Missouri Compromise favored the North.