What Is Disaster Recovery as a Service

What is disaster recovery as a service?

A) combines multiple network storage devices so they appear to be a single storage device
B) combines networks by splitting the available bandwidth into independent channels that can be assigned in real time to a specific device
C) combines the physical resources, such as servers, processors, and operating systems, from the applications
D) offers backup services that use cloud resources to protect applications and data from disruption caused by disaster