I already gave you the answer you just have to realize it. Follow this :
1. Login as Knowledge Manager.
2. Navigate to Admin tab under Knowledge Manager access.
3. Open knowledge category from left hand pane.
4. It will pop up a new window with Knowledge categories.
5. Open any existing category in edit mode.
6. Navigate to Permission tab and make changes as following .
7. Save the changes and it should be available during new KB creation as selectable category along with TOP
Thanks
ArunavaS