It is to be noted that the option that guarantees Brian can successfully revert his entire OneDrive to its state 15 days ago is- Brian has a paid version of Office 365. (Option B)
Having a paid version of Office 365 often includes features like advanced file versioning or document history in OneDrive.
This means Brian can access different versions of his document over time and revert it to the state it was 15 days ago. It's like having a safety net for his files.
The other options don't directly impact the ability to revert to a previous state and are more related to storage limits, software access, and file sharing.
Full Question:
Although part of your question is missing, you might be referring to this full question:
30. Brian uses OneDrive to back up important files on his computer to the cloud. Recently, he made some changes to a document that need to be reverted. He wants to revert his entire OneDrive to its state as it was 15 days ago. Which of the following, if true, guarantees that Brian can complete this task successfully?
a. Brian has a 5 GB limit on his OneDrive account storage.
b. Brian has a paid version of Office 365.
c. Brian has access to the OneDrive client on his laptop.
d. Brian has shared some of these files.