JAVA CERTIFICATION QUESTION: Read and write objects by using serialization

Given:

Constraint: Item class code can't be modified.

Which of the following changes allows an order to be properly serialized?

A. Add this new method to the Order class:

B. Add this new method to the Order class:

C. Add this new method to the Order class and mark the items instance variable transient:

D. None of the above

The answer is D.