Read the following selection from the section "The Debate Over Slavery Begins."

Slavery became a sticking point during the negotiations over political representation in Congress. Legally, enslaved black people were considered property. Yet Georgia and the Carolinas demanded they be counted as people when it came to calculating the number of representatives. Northern states refused.

What does the author mean by "sticking point"?

A
idea that started the negotiations
B
issue that led to disagreements
C
source of economic slowdown
D
series of insults back and for