Your current backup schedule involves differential backups of all data Monday through Saturday, with a full backup on Sunday. Last Saturday, one of your storage drives failed prior to running the daily backup. What must be done to recover the data on the failed drive?

restore the last full backup first.

Explanation:

Based on the information provided within the question it can be said that what you should do is restore the last full backup first. This is because a differential backup, backs up all the progressive changes made after the last full backup. Therefore the last full backup would contain all the data before the drive failed. Once this is done then you may restore the last successful differential backup prior to the drive failure.