Node – any requestor executing on the current node can access the pages.
Thread – the page is created in a single requestor thread, and can be accessed as often as needed by processing in that thread. Access by separate requestors causes the rule to create distinct pages, which might have different contents.
Requestor – all threads for the current requestor.
Note: Read/Write pages all have a Thread or Requestor page scope.
If you select scope as node, it will prompts for access group in load management tab, for remaining 2 scopes it wont ask anything.