Answer:
- Storming.
Step-by-step explanation:
The storming stage is categorized as the second stage of Tuckman's stages of 'team or group development' that involves the arising of conflicting opinions(as each member has a different perspective) from the various team members. This stage is one of the most crucial stages of team development as these conflicting opinions often lead to the fall or failure of the team and thus, require to be handled well by searching for a common viewpoint among all of them.
As per the given description, the 'storming' phase is being reflected as 'Cathy and Simon believe that they can lead the team' while the 'other members begin aligning themselves' that leads to a conflict among the team members that may turn fatal if not handled appropriately. Thus, the 'storming' phase is the answer.