DRAG DROP
Fabrikam has the Office 365 Enterprise E3 plan.
You must add the domain name fabrikam.com to the Office 365 tenant. You need to confirm ownership
of the domain.Which DNS record types should you use? To answer, drag the appropriate DNS record type to the
correct location or locations in the answer area. Each DNS record type may be used once, more than
once, or not at all. You may need to drag the split bar between panes or scroll to view content.
Answer: 
TXT is preferred because this will not harm your existing deployment. MX is your second option but not suggested for production environments.