Final answer:
High cohesiveness is likely to be a problem for a group when the group is working on a task that requires close cooperation between members (option C).
Step-by-step explanation:
High cohesiveness is likely to be a problem for a group when the group is working on a task that requires close cooperation between members. While high cohesiveness can positively contribute to teamwork and group success, it can also turn into a problem when the group becomes too focused on maintaining harmony and unity, hindering critical thinking and open discussion. In situations where close cooperation is necessary, such as problem-solving or decision-making tasks, high cohesiveness can prevent the group from considering different perspectives and exploring alternative solutions.