A major challenge in implementing cooperative arrangements as a macroprudential tool to manage cyber and ICT risks is aligning the diverse interests of different financial institutions and ensuring equitable contributions from all participants. Given the competitive nature of the financial sector, institutions may be hesitant to share sensitive information or resources, making it difficult to establish effective cooperative frameworks. Balancing collective security needs with individual institutional interests is a delicate task that requires careful negotiation and trust-building. These arrangements must find a way to harmonize the various competitive dynamics within the sector to enhance collective cyber resilience effectively.

A is incorrect while developing technological solutions is important, the primary challenge in cooperative arrangements is not the technical aspect but the alignment of interests among competitive entities.

C is incorrect; coordinating global strategies is a broader challenge that extends beyond the specific scope of cooperative arrangements within individual financial sectors.

D is incorrect because obtaining sufficient funding, while potentially challenging, is not considered the primary hurdle compared to overcoming the competitive hesitation to share sensitive information and aligning diverse institutional interests.