Implementing the required infrastructure to deliver reporting is indeed a significant challenge faced by model risk managers. Model risk reporting is a critical component of an organization's risk management framework. It provides insights into the model risk limit that the organization can tolerate. However, to deliver effective reporting, there is a need for appropriate infrastructure. This includes workflow tools and databases that enable the organization, management, and updating of data. Without the right infrastructure, it becomes difficult to measure the impact of models, define metrics linked to model risk appetite, determine an appropriate frequency of reporting, and aggregate reporting on individual models to provide a comprehensive and consistent view of model risk at a defined level of aggregation. Therefore, implementing the required infrastructure to deliver reporting is a significant challenge in model risk management.

Choice A is incorrect. While lack of funds can be a challenge in implementing the model, it is not the primary challenge highlighted specifically for designing and delivering effective model risk reporting.