Group insurance is contributory when:

This choice is misleading as it does not directly address the contribution aspect of the insurance premium. The collection of premiums by a third party may occur in various situations, but it does not define whether the plan is contributory or non-contributory. Therefore, it does not provide a relevant criterion for classifying the insurance type.

When the employer pays the entire premium, the insurance plan is classified as non-contributory. In such cases, employees do not contribute financially, meaning there is no shared premium responsibility. Thus, this choice contradicts the definition of a contributory plan.

Similar to choice A, this option focuses on the collection process rather than the contribution aspect. The involvement of a service provider in collecting premiums does not indicate whether the plan is contributory or non-contributory. Therefore, it is irrelevant to the question.