Explanation/Reference:
Explanation:
Though maintenance requirements vary based on complexity and performance work loads, a hardware maintenance schedule should be validated against the vendor-provided specifications. For business reasons, an organization may choose a more aggressive maintenance program than the vendor's program. The maintenance program should include maintenance performance history, be it planned, unplanned, executed or exceptional. Unplanned maintenance cannot be scheduled. Hardware maintenance programs do not necessarily need to be in line with historical trends. Maintenance schedules normally are not approved by the steering committee.

A screened-subnet firewall, also used as a demilitarized zone (DMZ), utilizes two packet filtering routers and a bastion host. This provides the most secure firewall system, since it supports both network- and application-level security while defining a separate DMZ network. A screened-host firewall utilizes a packet filtering router and a bastion host. This approach implements basic network layer security (packet filtering) and application server security (proxy services). A dual-homed firewall system is a more restrictive form of a screened-host firewall system, configuring one interface for information servers and another for private network host computers. A stateful inspection firewall working at the transport layer keeps track of thedestination IP address of each packet that leaves the organization's internal network and allows a reply from the recorded IP addresses.

Comprehensive and Detailed Step-by-Step Explanation:
When storage space is limited,incremental backupsare the most efficient because they store only the changes made since the last backup, reducing storage requirements.
* Option A (Correct):Incremental backupsonly store data that has changed since the last backup, significantly reducing storage usage while maintaining a historical record of changes.
* Option B (Incorrect):Mirror backupscreate an exact copy of the entire system, consuming significant storage space andnot retaining historical versions.
* Option C (Incorrect):Full backupscapture everything and require large amounts of storage, making them impractical for space-constrained environments.
* Option D (Incorrect):Annual backupsrefer to frequency rather than method. They do not inherently optimize storage usage.
Reference:ISACA CISA Review Manual -Domain 4: Information Systems Operations and Business Resilience- Covers backup strategies, storage management, and disaster recovery.