An exception to the comity clause in this context would be charging more money for out-of-state college tuition.
The comity clause generally supports the idea that states should respect each other's laws and judicial decisions; however, states are allowed to impose certain residency requirements that can lead to different rates for in-state and out-of-state students, which is often seen as a valid exception. The other options generally reflect actions that are more aligned with the principle of comity.