If you are asking if you can copyright an mrr product, the answer is no. If you are asking if you can copyright a plr product, the answer is no, you would need to do an extensive rewrite in order to make it unique. Then you can copyright it. You should always check the license included with each product. It will tell you what you can and can't do with it.
Is it OK if I submit free member downloaded eBook with license type private label right/master resale right and to state year of submission as copyright acquisition year?