What best describes customer dealing functions?

Client-facing roles dealing with retail customers and professional clients best describes customer dealing functions because these roles are designed to directly engage with clients to meet their needs. These functions often include providing advice, handling inquiries, processing transactions, and managing relationships. This aspect of customer dealing is crucial in financial institutions, as it focuses on the interaction and service provided to the clients, ensuring their requirements are understood and met effectively.

The other options do not accurately reflect the primary focus of customer dealing functions. Board governance roles pertain to oversight and strategic direction, which are essential but not directly related to customer interaction. Mandatory regulatory compliance roles involve adhering to laws and regulations but do not encompass the customer-facing aspect. Internal auditing tasks focus on the assessment of internal controls and processes, rather than direct client engagement. Thus, the choice highlighting client-facing roles aligns best with the function and purpose of customer dealings within financial services.