The cost of maintaining a control has grown to exceed the potential loss.

 The situation where the cost of maintaining a control has grown to exceed the potential loss is best described as an over-controlled environment, as it indicates that the control is not cost-effective and may be unnecessary or excessive. Insufficient risk tolerance, optimized control management, and effective risk management are not the best descriptions, as they do not reflect the imbalance between the control cost and the potential loss. References = CRISC Review Manual, 7th Edition, page 149.