Settlement of a case of violation of an average fuel economy standard is discretionary with the Administrator. The Administrator will consider settlement only to the extent:

(a) Necessary to prevent the insolvency or bankruptcy of the person seeking settlement, or

(b) That the violation of the average fuel economy standard resulted, as shown by the person seeking settlement, from an act of God, a strike, or fire, or

(c) That modification of a civil penalty assessed under this part is necessary to prevent lessening of competition, as determined and as certified by the Federal Trade Commission under section 508(b)(4) of the Motor Vehicle Information and Cost Savings Act, Pub. L. 94-163, 89 Stat. 911 (15 U.S.C. section 2008(b)(4)).