Arise

Watching everything I order of releasing and im now on the Arise "arch" and i see that Crunchyroll has an OVA but Im trying to avoid thoese as much as possible and I see Amazon Primes has it as well but it does not specify if its the OG or an OVA and I dont wana pay for it unless its the OG. Any help would be appreciated.I know nothing of the Arise chunk of Ghost media other then its a prequel.