"Regulatory Lag" Refers to the Period Between the Time When

"Regulatory lag" refers to the period between the time when

A) the natural monopolist's costs change and the time the regulatory agency adjusts the monopolist's prices.
B) the natural monopolist changes its prices and the time when the regulatory agency rules on that change.
C) the regulatory agency decides to regulate a firm and the time it actually accomplishes the task.
D) a firm is initially regulated by an agency and the time the firm "captures" that agency.
E) the regulatory agency decides to deregulate a firm and the time it actually accomplishes the task.