Passing moderation in re-chord time.
The C line date should be the composition year of the earliest piece on your release.
The P line should be as normal; whoever owns the copyright of the particular sound recording on your release (likely the performing artist).
Please note! Please ensure to list the original Composer within the Publishing Details of your classical release.
More on classical releases:
When should I use classical formatting when creating a release?
How should I format my track title for a classical release?
What do stores class as classical music?
How should I format my album title for a classical release?
Should I credit the composer as an artist for a classical release?