Final answer:
Increasing group size does not reduce social loafing; it can lead to less individual effort and more shared responsibility, which are conditions favorable for social loafing. The correct answer is option: C. Increasing the group size to enhance collaboration and motivation.
Step-by-step explanation:
The option that does not reduce social loafing is C. Increasing the group size to enhance collaboration and motivation. This is because increasing the size of the group can actually lead to a rise in social loafing, where individuals put forth less effort into a task due to the diffusion of responsibility within larger groups.
On the other hand, strategies like providing clear individual responsibilities, ensuring tasks are meaningful, and establishing a sense of accountability and recognition for individual contributions are known to effectively combat social loafing.