Let h = e-e be the amount that emissions, e, are reduced from the competitive level, e. the benefit of reducing emissions is b(h) = ah". the cost is c(h) hp. if the benefit is increasing but at a diminishing rate in h, and the cost is rising at an increasing rate, what are the possible ranges of values for a, ? , and ? ? o a. a must be positive, a and b must be between zero and 1 o b. a must be negative, ar must be between zero and 1, ß must be greater than one. c. a must be positive, must be between zero and 1, ß must be greater than one. o d. a must be negative, a and ß must be greater than one