It's a combination of your template, K2 and your joomla settings.
First, go to Content > Category Manager > Options icon and check the global options for your category display.
Then go to the individual categories, and check those to see if they agree with the global options.
Then go to the menu item that points to it and check to see which basic options, layout options and page display options.
Do the same for K2 categories since you have k2 categories installed.
All of these have to be set correctly.
Check those out and if they are still showing, let us know and we'll walk you through eliminating them altogether.
Get back to us.
Cheers,
Ed