HOTSPOT
Your company has a Microsoft 365 subscription that contains the following domains:
Contoso.onmicrosoft.com
Contoso.com
You plan to add the following domains to Microsoft 365 and to use them with Exchange Online:
– Sub1.contoso.onmicrosoft.com
– Sub2.contoso.com
– Fabrikam.com
You need to identify the minimum number of DNS records that must be added for Exchange Online to receive inbound email messages for the three domains.
How many DNS records should you add? To answer, select the appropriate options in the answer area. NOTE: Each correct selection is worth one point.
Answer: 
Explanation:
Box 1: 2
You don’t need to verify Sub1.contoso.onmicrosoft.com because the onmicrosoft.com domain and DNS is managed by Microsoft. You also don’t need to configure an MX record for Sub1.contoso.onmicrosoft.com because that will be done by Microsoft.
For sub2.contoso.com, you don’t need to verify the domain because you have already verified its parent domain contoso.com. However, you do need an MX record to direct email for that domain to Exchange Online.
For Fabrikam.com, you will need to verify the domain. You will need an MX record to direct email for that domain to Exchange Online.
Box 2: 0
You ‘should’ create CNAME records for autodiscover to point your email clients to Exchange Online to connect to the mailboxes. However, you don’t have to. You could configure the email client manually. Therefore, the minimum number of CNAME records required is zero.