1.To change the visibility, navigate to General Applications > Questions, then hover over Questions again bring up a dropdown menu and select Import Data.

Accessing the Import Data
Once in the Import Data section, there are two tabs; one for information that is visible to Applicants and another that is information visible to Administrators. Within each tab is the Reviewable column, which indicates whether or not pieces of data are also visible with Reviewers. 
Selecting a Question to Edit

2. To change a questions visibility, click the Edit button. 
3. Unmark the Reviewable checkbox to hide information from reviewers. Or mark the Reviewable checkbox to show the information to Reviewers.
4. Click the Update for All Opportunities button. 
Unchecking the Reviewable Box
5. Click the Update Questions button on the main Import Data section. 
6. Repeat these steps for all questions that should be visible to reviewers.
 
Note: Making a field Reviewable shows it to all Reviewer Groups. Unchecking the Reviewable hides from all Reviewer Groups. It's a system-wide setting, but it can be toggled on and off as needed.