Which command is used to view all ACLs on the router?

The command used to view all ACLs (Access Control Lists) on a router is "show access-lists." This command provides a comprehensive overview of all configured access lists on the device, displaying each access list's number or name along with the detailed rules that make up the lists.

When using "show access-lists," you can see both standard and extended ACLs, along with their associated permit and deny statements. This is crucial for network management and security, as it gives you insight into the traffic rules that the router is enforcing.

Other choices do not provide the same breadth of information as "show access-lists." For example, "show ip access-lists" specifically targets only the IP access lists, which limits the scope of the output. "Display access-lists" and "list access-lists" are not valid commands in Cisco's IOS command set and will not execute successfully on a router. Therefore, "show access-lists" stands out as the correct command for viewing all access lists comprehensively.