Inconsistent device security is the primary challenge for an information security manager when deploying a bring your own device (BYOD) mobile program in an enterprise because it increases the risk of data breaches and compromises. A BYOD mobile program allows employees to use their personal devices, such as smartphones, tablets, or laptops, to access the organization's network, applications, and data. However, personal devices may have different operating systems, versions, configurations, and security settings than the organization's standard devices. Moreover, personal devices may not be updated regularly, may have unauthorized or malicious apps installed, or may not have adequate protection against malware or theft. Inconsistent device security makes it difficult for the information security manager to enforce and monitor the security policies and controls across all devices, as well as to ensure compliance with the regulatory requirements for data privacy and security. Therefore, inconsistent device security is the correct answer.
Reference:
https://simplemdm.com/blog/challenges-of-bring-your-own-device-byod-policy/
https://www.timedoctor.com/blog/byod-pros-and-cons/
https://www.ncsc.gov.uk/files/NCSC-Vendor-Security-Assessment.pdf

Routine administration of all aspects of security is delegated, but senior management must retain overall responsibility. The information security officer supports and implements information security for senior management. The data owner is responsible for categorizing data security requirements. The data custodian supports and implements information security as directed.

Explanation/Reference:
Explanation:
In a major disaster, staff can be injured or can be prevented from traveling to the hot site, so technical skills and business knowledge can be lost. It is therefore critical to maintain an updated copy of the detailed recovery plan at an offsite location. Continuity of the business requires adequate network redundancy, hot site infrastructure that is certified as compatible and clear criteria for declaring a disaster. Ideally, the business continuity program addresses all of these satisfactorily. However, in a disaster situation, where all these elements are present, but without the detailed technical plan, business recovery will be seriously impaired.