HOTSPOT
Your company has a SharePoint Server 2013 server farm.
Users report that they cannot add iframes to SharePoint pages that point to content on external
websites.
You need to ensure that the users can add content to iframes from a list of predefined external sites.
What should you configure? (To answer, select the appropriate link in the answer area.)
Answer: 
Explanation:
Note: In regards to the cross-domain comments, even if it is cross-domain, you can allow the target
domain under Site Collection Settings, HTML Field Security.
I agree