About Question enthuware.ocpjp.v17.2.3448 :

[likejudo]

If "None of the above are correct", then what is the correct answer?

[admin]

That option is correct.
The rules are given in the explanations. For example, option 1 says Print must be an interface and it is wrong because, as the explanation says,

Ideally, Print should be an interface or an abstract class but there is no such technical restriction.

As per JLS Section 7.7.4:
The service must be a class type, an interface type, or an annotation type. It is a compile-time error if a provides directive specifies an enum type as the service.

You may do the same for other options.