A definition of “Done” in case of many Development Teams working on a single product

The open scrum test contains the following question:

When many Development Teams are working on a single product, what best describes the definition of “Done?”

A proper answer according to the test is:

All Development Teams must have a definition of “Done” that makes their combined work potentially releasable.

However, there is another option there, which is:

Each Development Team uses its own but must make their definition clear to all other teams so the differences are known.

And my question is that I don’t really understand what’s the significant difference between these two options? I deem them as very similar. They both complete each other. And I don’t really think that there is anything wrong in the second statement.

Could someone give me a glue how should be more confident about why the proposed correct answer is only one correct in this particular case?