Which statement is true concerning a functional iRule?

iRules are based on Tool Command Language (Tcl), an open-source scripting language, not a proprietary syntax language.

iRules are event-driven scripts that execute specific Tcl code in response to network events like `CLIENT_ACCEPTED` or `HTTP_REQUEST`. An event declaration is fundamental as it defines when the iRule's logic is applied to the traffic flow, without which the iRule would never be triggered.

While many iRules use conditional statements for logic, it's not a mandatory requirement for functionality; a simple iRule might perform an action unconditionally.

Not all iRules assign a pool; an iRule can perform various actions like logging, HTTP header modification, or redirection without ever directly selecting a pool.