Your question is Office 365 and Security Concepts. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Talk about a tenant-to-tenant Office 365 migration, including hypothetical issues like a Contact object not dirsyncing from on-prem to Office 365, and explain SPM, DKIM, and DMARC.