What happens if an attacker attempts a double-tagging attack?

If you change the native VLAN on the trunk port to an unused VLAN, what happens if an attacker attempts a double-tagging attack?
A. The trunk port would go into an error-disabled state.
B. A VLAN hopping attack would be successful.
C. A VLAN hopping attack would be prevented.
D. The attacked VLAN will be pruned.