BT composite that sequentially executes tasks until first [code]SUCCESS[/code]. BTSelector executes its child tasks sequentially, from first to last, until any child returns [code]SUCCESS[/code]. If a child task results in [code]FAILURE[/code], BTSelector will immediately execute the next child task until one of them returns [code]SUCCESS[/code] or all of them result in [code]FAILURE[/code]. BTSelector and [BTSequence] are two of the most common building blocks of behavior trees. Essentially, while [BTSequence] is similar to a boolean AND operation, BTSelector is similar to a boolean OR operation. Selectors enable the behavior tree to respond to changes in the environment and trigger transitions between various fallback behaviors. Returns [code]RUNNING[/code] if a child task results in [code]RUNNING[/code]. BTSelector will remember the last child task that returned [code]RUNNING[/code], ensuring it resumes from that point in the next execution tick. Returns [code]SUCCESS[/code] if a child task results in [code]SUCCESS[/code]. Returns [code]FAILURE[/code] if all child tasks result in [code]FAILURE[/code].