Keion works as a freelancer creating websites and designing…

Keion works as a freelancer creating websites and designing logos for clients. He recently had a hard drive failure and lost work for a client, and he would like to prevent the same type problem from happening again. Keion does not want to rely on a backup but would like a way to ensure that his data is safe on his computer. You recommend that he create a RAID array that will duplicate his work onto two disks.   What RAID configuration should you recommend to Keion?