I would say the best answer is A. Answer choice B is rather absurd and answer choice C doesn't exactly make any sense.
I. DELETE the underlined portion.
It important for the students to stay together because collectivism will help them to learn and develop many new skills.
<u>Explanation:</u>
Research shows that when students work together collectively in small groups, it not only help them to develop critical thinking, but it also helps in improving their attitude towards learning.
When students stay together, it leads in nurturing team relationship which further helps them in involving in team building activity. Apart from this, by learning, working, and staying together students develop the values of team spirit, helpfulness, and the power that lies in being united.