When John detects a high load on the sync interface, the recommended solution is to implement a delay in the sync process for short-lived connections like HTTP. Here's an explanation of each option:

A. Delaying the sync for 2 seconds for short connections like HTTP services is a common practice to reduce the load on the sync interface. This allows the interface to handle the incoming connections more effectively.

B. Adding a second interface to handle sync traffic might be a viable solution, but it can be more complex and costly compared to implementing a delay for short connections.

C. Not syncing short connections like HTTP services is not a recommended approach because it may lead to synchronization issues and potential data inconsistencies between cluster members.

D. Delaying the sync for ICMP (ping) services is not a common practice and may not effectively address the high load issue on the sync interface.

Therefore, option A is the most recommended solution as it addresses the issue by introducing a delay for short-lived connections, optimizing the sync process without causing synchronization problems.

References: Check Point Certified Security Expert (CCSE) R81 documentation and learning resources.