High Availability (HA) timer settings in PAN-OS control failover speed and stability. The Recommended profile (Option D) is the default and provides balanced timers (e.g., 1000ms heartbeat interval) suitable for typical deployments, ensuring reliable failover without excessive sensitivity.
Option A (Critical profile) uses faster timers (e.g., 100ms) for critical environments, not typical ones. Option B (Moderate) isn't a predefined profile. Option C (Aggressive) uses fast timers (e.g., 200ms), not slower ones.
Documentation specifies "Recommended" for standard use.
Reference: PAN-OS 11.2 Administrator's Guide, "High Availability" section - HA Timer Profiles.