Which of these belongs in the empty box?
a. Electing a president
b. National power versus states' rights
c. Slaves used to determine representation
d. Taxation of exports
![Which of these belongs in the empty box a Electing a president b National power versus states rights c Slaves used to determine representation d Taxation of exp class=](https://us-static.z-dn.net/files/ddb/06adf33ba317abb74773a3d2a300bb6f.png)