Don't know which power adapter to use

I have an old My Book -WD5000H1Q-00, that I had put away into storage. Now, I want to look for some files, but I don’t know which of the numerous power adapters that I have laying around is the correct one to use. I have tried looking online, but nowhere that I looked has given me any insight as to the amps it needs. I have a couple that “could” work, but I’m not sure. One is 15V DC 1000mA, One is 5V DC 2A, and one is 12V DC 750mA. These are the only ones that the adapter plug fits into the DC IN port of the My Book. Any help would be great! Thanks

From the model provided, you have a My Book Studio Edition.
You can find a list of drives and the power requirements they need below.