Which statement is true concerning a functional iRule.

iRules are written in Tcl (Tool Command Language) with F5-specific extensions, not a proprietary language invented solely by F5.

iRules are event-driven scripts, and every functional iRule must include at least one event declaration such as 'when CLIENT_ACCEPTED' or 'when HTTP_REQUEST' to specify the trigger point for execution. Without an event declaration, the BIG-IP has no context for when to invoke the iRule commands, making it non-functional.

Conditional statements are optional; a simple iRule can perform an unconditional action such as logging or a static pool assignment inside an event block without any if/else logic.

Pool assignment statements are not required; an iRule may perform other actions such as HTTP header insertion, redirects, or logging without ever assigning traffic to a pool.