The correct answer is C. Reduced costs.
When you are working in an organization, it is true that teamwork makes things easy. Your work completion speed improves, stress decreases, overall workplace cohesiveness improves and destructive internal competition also reduces. So it helps in many ways. But it does not have any significant impact on the cost of the work, as cost is dependent on a lot of other major factors as well. Teamwork alone doesn’t impact cost much.