which of the following are defined by default as a critical device?

There are a number of built-in critical devices, and the administrator can define additional critical devices. The default critical devices are:
-The cluster interfaces on the cluster members.
-Synchronization — full synchronization completed successfully.
-Filter — the Security Policy, and whether it is loaded.
-cphad — which follows the ClusterXL process called cphamcset.
-fwd — the Security Gateway daemon.

https://sc1.checkpoint.com/documents/R76/CP_R76_ClusterXL_AdminGuide/7298.htm