Correct Answer: D
The two high availability modes are New and Legacy. High availability (HA) is a feature that allows you to create a cluster of two or more Security Gateways that act as a single entity to provide redundancy and reliability for your network traffic. HA ensures that if one Security Gateway fails or becomes unavailable, another Security Gateway in the cluster takes over its role seamlessly and continues to process the traffic. HA also provides load balancing and synchronization of the cluster members. The New mode is the recommended mode for HA clusters, as it provides better performance, scalability, and stability than the Legacy mode. The New mode uses the ClusterXL mechanism to manage the cluster members and the state synchronization. The Legacy mode uses the High Availability Security Extension (HASE) mechanism to manage the cluster members and the state synchronization. The Legacy mode is supported for backward compatibility with older versions of Check Point products, but it has some limitations and disadvantages compared to the New mode.