RBAC stands for Role-Based Access Control, which is a method of restricting access to data and resources based on the roles or responsibilities of users. RBAC simplifies the management of permissions by assigning roles to users and granting access rights to roles, rather than to individual users. RBAC can help enforce the principle of least privilege and reduce the risk of unauthorized access or data leakage. The other options are not as suitable for the scenario as RBAC, as they either do not prevent access based on responsibilities, or do not apply a simplified format.

Change management involves formally reviewing, approving, and implementing changes through a controlled process, such as applying an update after receiving approval from a governing board.

The $1 million represents a predefined trigger point at which a specific risk response is initiated, indicating the level at which the organization decides to take action by transferring the risk through insurance.

A load balancer is the most appropriate solution to ensure accessibility of a business-critical application during peak usage times. It distributes incoming network traffic across multiple servers, optimizing resource utilization, maximizing throughput, minimizing response time, and avoiding overload on any single server. This is particularly crucial for a multinational bank's customer-facing application during high-traffic periods.