Salvador, a grocery store manager, is preparing his overnight group for the annual store inventory. Salvador tells the group that he knows a lot of workers hate the inventory, but it is important that the company knows what their stock levels are, and what products are not selling. He also reminds the workers that management gave them the option to do the inventory during the day or at night, and they chose the night option to make it easier to complete the inventory without shoppers present. Which work group team goal criterion was Salvador expressing in his talk with the workers? Effective goals are challenging Effective work group teams develop explicit member roles and rules Effective goals serve a common purpose Effective goals are shared