Which command can you use to verify the number of active concurrent connections?

The choice of the command that verifies the number of active concurrent connections is accurate because "fw ctl pstat" is designed to provide various statistics about the Check Point firewall. Specifically, this command gives information regarding connections, including the number of active and total connections currently being managed by the firewall.

This command is a valuable tool for administrators because it aggregates a wide range of performance metrics, including system state information, so they can assess how many connections the system is handling at any given time.

The other provided options either serve different functions or are not valid commands within the Check Point firewall management context. Option choices that imply showing connections (like "show all connections" or "show connections") do not correspond to actual commands in the Check Point command line interface. Thus, "fw ctl pstat" stands out as the appropriate command for monitoring active concurrent connections.