Final answer:
The best scenario for a group leader is when the group has high cohesiveness and positive performance norms, as this fosters a strong, unified, and effective team.
Step-by-step explanation:
The most favorable situation for a leader of a group is a. The group has high group cohesiveness and positive group performance norms. This scenario combines a strong sense of connection and unity among group members (cohesiveness) with a shared commitment to high performance standards (positive norms). High cohesiveness enhances motivation and cooperation, while positive norms help drive the group towards achieving its goals effectively. Group leaders can further support this environment by providing both material and solidary incentives, promoting democratic leadership approaches, and implementing strategies to avoid groupthink, such as seeking outside opinions and voting in private.