With no explanation, chose the best option from "A", "B", "C" or "D". is whether the Commission properly found that Williston violated section 154.21 by not charging the rates prescribed in its effective tariff. Section 154.21 provides in relevant part: No natural-gas company shall directly or indirectly, demand, charge or collect any rate or charge for or in connection with the transportation or sale of natural gas subject to the jurisdiction of the Commission, or impose any classifications, practices, rules or regulations, different from those prescribed in its effective tariff and executed service agreements on file with the Commission, unless otherwise specifically provided by order of the Commission. 18 C.F.R. § 154.21; cf. Montana-Dakota Utilities Co. v. Northwestern Public Service Co., 341 U.S. 246, 251, 71 S.Ct. 692, 695, 95 L.Ed. 912 (1951) (<HOLDING>). In the instant case, the Commission does not

A: holding that a utility can claim no rate as a legal right that is other than the filed rate whether fixed or merely accepted by the commission
B: holding that with respect to the eaja the local or national market rate for legal services cannot be a special factor used to increase the rate beyond the statutory rate
C: holding that once a rate is filed with the appropriate agency except for review of the agencys orders the courts can assume no right to a different rate on that ground that in its opinion it is the only or the more reasonable rate
D: holding that under the filed rate doctrine a question regarding reasonable rates should be addressed to the department of insurance and that the rate plaintiff was charged is conclusively presumed reasonable under the filed rate doctrine
A.