Answer:
D - may check Marcy's immigration status, but may not arrest Marcy because a state may not make it a crime to fail to carry documentation.
Explanation:
It's not a crime to fail to carry documentation in many places. In this particular case, given that Marcy didn't carry documentation, the officer could make a judgment call to see how to procede. He could search the car in their database, search her; many things could be done to determine if she should be arrested, her car held, etc.