Final answer:
The premiums charged for group benefits are not guaranteed and can change over time based on factors such as the number of employees, their ages, and the overall health of the group.
Step-by-step explanation:
The correct response given by the insurance agent is a) The premiums charged for group benefits are not guaranteed.
Insurance premiums for group plans are not fixed and can change over time. Factors such as the number of employees, their ages, and the overall health of the group can affect the premiums charged. It is important for Bentley to understand that the premiums he pays for the group plan may change in the future.