What Is the Advantage of Having a "Hot Site" as a Back-Up

What is the advantage of having a "hot site" as a back-up control?

A) Power and space are available at the site to set up processing equipment on short notice (e.g., after a disaster) ..
B) The site is located in another branch of the company in a neighboring county.
C) The system is configured in a manner similar to the normal day-to-day processing and is available for immediate use.
D) All of the above are advantages of having a hot site.