group C is corrently at the Performing stage.
In the performing stage, the group has built group patterns and settled most interpersonal concerns, the center of the group transfers to its tasks. The group now has an edifice and a process of striving together that will aid relinquishing the goals that group members have anchored for themselves.
The team has a shared idea and is capable to survive on its individual feet with no intervention or support from the leader. There is a locus on over-achieving intentions, and the team performs most of the choices against the criteria corresponded with the leader.