At the end of a project, you upload project documents to a Microsoft SharePoint Online...

At the end of a project, you upload project documents to a Microsoft SharePoint Online library that contains

many files. The following is a sample of the project document file names:

aei_AA989.docx

bci_WS098.docx

cei_DF112.docx

ebc_QQ454.docx

ecc_BB565.docx

All documents that use this naming format must be labeled as Project Documents:

You need to create an auto-apply retention label policy.

What should you use to identify the files?