Final answer:
The Business Unit Director is most qualified to provide RTO/RPO metrics for a BIA on an ERP system because of their detailed knowledge of business processes and the operational impacts of downtime.
Step-by-step explanation:
The Chief Information Security Officer (CISO) is conducting a Business Impact Analysis (BIA) with the intention of establishing appropriate Recovery Time Objectives (RTO) and Recovery Point Objectives (RPO) for the organization's Enterprise Resource Planning (ERP) system. The most qualified individuals to provide the necessary metrics for RTO and RPO would likely be the Business Unit Director. They have the comprehensive understanding of the business processes that the ERP supports, as well as the potential impact on the business if those processes were to be disrupted. Data owners and Business Unit Directors have the expertise and perspective to determine how long business processes can tolerate downtime (RTO) and how much data loss could be tolerated (RPO), which are critical components for the BIA.
While the Data Custodian is responsible for the safe custody, transport, and storage of the data, they might not be qualified to provide RTO/RPO metrics which are closely tied to business needs. Security Analysts, although they have technical expertise, might not have the required business process insight. The CEO, despite having an overall vision of the company, might not be involved in daily operational details to the extent necessary for precise RTO/RPO determination. Thus, the Business Unit Director, being closely involved with the operational aspects and the impacts of downtimes, would be the most appropriate person to interview for RTO/RPO metrics.