Answer: Norming
Explanation: In simple words, it is the third stage in group development in which the members of the group starts understanding each others perceptions and the strategic forces comes into play leading to alignment of their goals.
Generally in this stage, all the members starts believing that they can achieve better results if they work together in harmony.
In the given case, Jack's groups have started developing close relationships with each other ans have started working in harmony.
Hence we can conclude that they are at morning stage.