You deploy a Microsoft Hyper-V Server 2008 R2 server. You will back up the server by using Microsoft System Center Data Protection Manager （DPM） 2007 with SP1. Your virtual environment includes the virtual machines （VMs） shown in the following table. You need to configure the DPM protection group to minimize server downtime during business hours and to provide the best recovery point objective （RPO）.    What should you do？（）

• A、Set synchronizations to run every 15 minutes during business hours
• B、Set synchronizations to run every 30 minutes during business hours
• C、Set synchronizations to run every 45 minutes during business hours
• D、Perform express full backups every 60 minutes during non-business hours