The correct answer is A. Differences in infrastructure capabilities.

A reciprocal arrangement is a recovery strategy in which another organization agrees to provide facilities or processing capability during a disruption. The most important consideration is whether the other party’s infrastructure can actually support the recovering organization’s critical systems, workloads, data, applications, network connectivity, capacity, and recovery time requirements.

If infrastructure capabilities are incompatible or insufficient, the reciprocal arrangement will fail regardless of whether security policies, service expectations, or staff skills are acceptable. For example, if the recovery partner lacks compatible hardware, sufficient processing capacity, adequate storage, required network connectivity, or application platform compatibility, the organization may not be able to recover critical services.

ISACA defines a recovery strategy as an approach that ensures recovery and continuity in the face of a disaster or major outage, and it lists a consortium or reciprocal agreement as one possible recovery methodology. ISACA also describes recovery solutions in terms of the technical, physical, procedural, and human resources needed to recover within defined time and cost limits.

Option B is important because security requirements must still be maintained during recovery, but security-policy differences are secondary if the environment cannot technically support recovery.

Option C is important because service levels should be aligned, but service expectations cannot be achieved without adequate infrastructure capability.

Option D is important because staff competence affects recovery execution, but the first practical question is whether the reciprocal site can support the required systems and processing.