There is no cud because a cud involves the rim and there is nothing wrong with the rim. The mark on the 0 is damage
It would be a cud. A cud is just a die break, typically off the most susceptible part of the die, the rim. There are interior ones. We call those "retained." It just means the same thing, they're breaks inside the rim, not off it.
How can an interior die break be a cud? A cud isn't "typically" off the rim, it's "always" includes the rim For reference https://www.error-ref.com/cuds/
Definitely a contact mark. The rim is unbroken so it’s not a cud. A cud is a die break on the rim, not the date which is near the rim.