This could be an issue with corrupted data, so you might try deleting any title updates and re-downloading them.
- From the Xbox Dashboard, scroll to the right and find the "Settings" tab
- Press A on "System."
- Move down to "Storage"
- Select the entry for your Xbox's internal storage.
- Pick "Games and Apps" and then scroll down to the entry for Black Ops 2.
- In this menu, delete anything that has a yellow exclamation mark or anything that reads "Title Update." Be sure NOT to delete your save game!
Then try running Black Ops 2, and you should be prompted to update the game. After the update is done, see if the problem persists.
If you still have the problem, it's probably either the disc or your Xbox - if you can borrow or rent a copy of the game, try that, or take your disc to a friends' Xbox and see if it exhibits the same problem.