Cleo finds herself frequently searching for messages from particular senders or with specific subjects. What should she create
to increase efficiency for these searches?
Index
Outlook Rule
Instant Search
Search Folder

The element she can create to increase efficiency for these searches is:

Search Folder

Explanation:

The reasons behind this are that index in the first place indexes by themselves don't facilitate the job of looking quickly at a certain e-mail. Because they show the user all of them. Second, outlook rules are certain guidelines that the user can program to group certain emails and send them to certain folders. However, they don't play a crucial part in quick searches. We have two options that could make this: instant search of folder search. Instant search works by general categories, of emails, events, and contacts. But search folders give the user certain characteristics the emails can have so the user can choose which emails to see. Thus, this is the correct answer.