You have an Exchange Online tenant that contains several hundred mailboxes.
Several users report that email messages from an SMTP domain named @fabrikam.com often fail to be delivered to their mailbox.
You need to increase the likelihood that the email messages from the @fabrikam.com are delivered successfully to the users in the tenant.
A. From the Security & Compliance admin center, modify the anti-spam policy settings.
B. From the Security & Compliance admin center, modify the DKIM settings.
C. From your public DNS zones, create a Sender Policy Framework (SPF) TXT record.
D. From the Security & Compliance admin center, create a new ATP anti-phishing policy.
