The question asks about the least amount of redundancy for a company's network that wants to add a local backup data center.
The answer is not B, because a hot site is a fully operational data center that can take over the primary site's functions immediately in case of a disaster. It has the most amount of redundancy, as it replicates the primary site's data, applications, and hardware.
The answer is not C, because a cloud site is a data center that is hosted by a third-party provider on the internet. It can provide a high level of redundancy, as it can scale up or down according to the demand and availability of resources. It also offers flexibility and cost-efficiency for the company.
The answer is not D, because a warm site is a partially operational data center that can take over the primary site's functions within a short time in case of a disaster. It has a moderate amount of redundancy, as it has some of the primary site's data, applications, and hardware, but not all of them.
The answer is A, because a cold site is a data center that is not operational and requires a lot of time and effort to set up and activate in case of a disaster. It has the least amount of redundancy, as it has none of the primary site's data, applications, or hardware. It only has the basic infrastructure, such as power, cooling, and network connectivity.
Reference:
1: CompTIA Network+ N10-008 Study Guide, Chapter 5: Network Management, Section 5.3: Network Disaster Recovery, p. 295
2: CompTIA Network+ N10-008 Study Guide, Chapter 5: Network Management, Section 5.3: Network Disaster Recovery, p. 296
3: CompTIA Network+ N10-008 Study Guide, Chapter 5: Network Management, Section 5.3: Network Disaster Recovery, p. 297
4: CompTIA Network+ N10-008 Study Guide, Chapter 5: Network Management, Section 5.3: Network Disaster Recovery, p. 298