With no explanation, chose the best option from "A", "B", "C" or "D". heavily upon the case of In re Grynberg, 986 F.2d 367 (10th Cir.1993). Because the tax claim was non-dischargeable under 11 U.S.C. § 1141(d)(2), the Grynberg court held that the IRS was not obligated to file a claim in the bankruptcy proceedings and was free to pursue its claim outside the bankruptcy proceedings. That case, however, is distinguishable from the case at bar because there the IRS had not filed a proof of claim for the gift taxes at issue and the debtor's plan of reorganization did not provide for the payment of the tax liability. In the case at bar, the IRS had filed proofs of claim on account of its non-dischargeable tax claim, thereby consenting to the Bankruptcy Court's determination of the amount of the claim. See In re Martin, 150 B.R. 43, 46-48 (Bankr.S.D.Cal.1993) (<HOLDING>). 2 . The debtors argue, in the alternative,

A: holding that a decedents tax settlement with the irs did not establish the value of his estates claim against the irs as a matter of law
B: holding that irs was bound by plan and bankruptcy codes method of determining amount of nondischargeable claim where irs had filed proof of claim for nondischargeable tax debt
C: holding that the irss full participation in the bankruptcy proceeding in relation to an income tax debt did not bar it from collecting a gift tax debt that had also been listed in the debtors schedules where the irs did not file a proof of claim and the debtor did not force the irs into the proceeding on the gift tax debt
D: holding nondischargeable postpetition interest on debt that was determined to be nondischargeable under section 523a2 as obtained by fraud
B.