To meet the requirements of centrally managing configurations, pushing policies, remotely wiping devices, and maintaining an asset inventory, the best solution is to implement a Mobile Device Management (MDM) solution.
MDM Capabilities:
Central Management: MDM allows administrators to manage the configurations of all devices from a central console.
Policy Enforcement: MDM solutions enable the push of security policies and updates to ensure compliance across all managed devices.
Remote Wipe: In case a device is lost or stolen, MDM provides the capability to remotely wipe the device to protect sensitive data.
Asset Inventory: MDM maintains an up-to-date inventory of all managed devices, including their configurations and installed applications.
Other options do not provide the same comprehensive capabilities required for managing specialized endpoints.
Reference:
CompTIA SecurityX Study Guide
NIST Special Publication 800-124 Revision 1, "Guidelines for Managing the Security of Mobile Devices in the Enterprise"
"Mobile Device Management Overview," Gartner Research

For a disaster recovery (DR) plan requiring immediate data availability, the first step is understanding what needs to be protected and recovered. Identifying critical business processes and their associated software and hardware requirements establishes the foundation for the DR plan. This ensures that backups and recovery mechanisms align with business priorities, meeting the "moment's notice" requirement.
Option A:A change management plan is important for system consistency but doesn't directly address immediate data availability in a DR context.
Option B:Hiring staff supports execution but doesn't define what needs to be recovered or how. It's a later step.
Option C:A warm site (a partially operational backup site) is a good DR solution, but designing it comes after identifying critical processes and resources.
Option D:This is the first step in any DR planning process-knowing what's critical ensures the plan meets availability goals efficiently.

To ensure the most secure way of keeping a legacy system (COL) operating until a new solution is available, isolating the system and enforcing strict firewall rules is the best approach. This method minimizes the attack surface by restricting access to only the necessary endpoints, thereby reducing the risk of unauthorized access and potential security breaches. Isolating the system ensures that it is not exposed to the broader network, while firewall rules control the traffic that can reach the system, providing a secure environment until a replacement is implemented.
Reference:
CompTIA SecurityX Study Guide: Recommends network isolation and firewall rules as effective measures for securing legacy systems.
NIST Special Publication 800-82, "Guide to Industrial Control Systems (ICS) Security": Advises on isolating critical systems and using firewalls to control access.
"Network Security Assessment" by Chris McNab: Discusses techniques for isolating systems and enforcing firewall rules to protect vulnerable or legacy systems.
By isolating the system and implementing strict firewall controls, the organization can maintain the necessary operations securely while working on deploying a new solution.

HMAC (Hash-based Message Authentication Code)ensures the integrity and authentication of API requests without exposing static or hard-coded private keys. It uses a secret key and a hash function, preventing replay attacks and tampering. VPNs secure the transport layer, MFA protects user accounts (not API-to-database communications), and DSA is a signature algorithm but does not address hard-coding risk directly.
Reference:

B . Pre-commit code linting: Linting tools analyze code for syntax errors and adherence to coding standards before the code is committed to the repository. This helps catch minor code issues early in the development process, reducing the likelihood of deployment failures.
D . Automated regression testing: Automated regression tests ensure that new code changes do not introduce bugs or regressions into the existing codebase. By running these tests automatically during the deployment process, developers can catch issues early and ensure the stability of the development environment.
Other options:
A . Software composition analysis: This helps identify vulnerabilities in third-party components but does not directly address code quality or deployment failures.
C . Repository branch protection: While this can help manage the code submission process, it does not directly prevent deployment failures caused by code issues or security check failures.
E . Code submit authorization workflow: This manages who can submit code but does not address the quality of the code being submitted.
F . Pipeline compliance scanning: This checks for compliance with security policies but does not address syntax or regression issues.
Reference:
CompTIA Security+ Study Guide
"Continuous Integration and Continuous Delivery" by Jez Humble and David Farley OWASP (Open Web Application Security Project) guidelines on secure coding practices