
Explanation:

Box 1: Full and log backups only
Make sure to take every backup on a separate backup media (backup files). Azure Database Migration Service doesn ' t support backups that are appended to a single backup file. Take full backup and log backups to separate backup files.
Box 2: WITH CHECKSUM
Azure Database Migration Service uses the backup and restore method to migrate your on-premises databases to SQL Managed Instance. Azure Database Migration Service only supports backups created using checksum.
Reference:
https://docs.microsoft.com/en-us/azure/dms/known-issues-azure-sql-db-managed-instance-online Basic Concept: This question tests choosing the correct Azure migration approach by matching the source platform, target service, downtime tolerance, and administrative effort.
Why the selected answer is Correct: The selected values fit this scenario because they apply the required Azure SQL configuration at the correct scope and sequence: You need to perform an online migration of DB1 to an Azure SQL Database managed instance by using Azure Database Migration Service.
Why the alternate choices are Wrong: The alternate selections would either use a migration tier that does not match the downtime requirement, choose a network resource that does not support the migration path, or add an unnecessary deployment component.