With no explanation, chose the best option from "A", "B", "C" or "D". courts as to the availability of equitable defenses against allegations that stock transactions are viola-tive of the 1933 Act, see Annot., 26 A.L.R. Fed. 682, 685 (1976), several federal courts have recognized that purchasers may be estopped by their conduct from asserting an issuer’s failure to comply with the registration provisions of the 1933 Act. See Meyers v. C & M Petroleum Producers, Inc., 476 F.2d 427, 429-30 (5th Cir.), cert. denied, 414 U.S. 829, 94 S.Ct. 56, 38 L.Ed.2d 64 (1973); Fuller v. Dilbert, 358 F.2d 305 (2d Cir. 1966), aff'g 244 F.Supp. 196, 214 (D.N.Y. 1965); Straley v. Universal Uranium & Milling Corp., 289 F.2d 370, 373 (9th Cir. 1965); Belhumeur v. Dawson, 229 F.Supp. 78, 86 (D.Mont.1964). Cf. Can-Am Petroleum Co. v. Beck, 331 F.2d 371, 373-74 (10th Cir. 1964) (<HOLDING>). We find that the same evidence we relied on

A: recognizing doctrine
B: recognizing but finding inapplicable pure question of law exception to doctrine of exhaustion
C: recognizing in loco parentis as statutory ground of visitation rights but finding it inapplicable on facts presented
D: recognizing availability of in pari delicto doctrine as defense to registration violation but finding it inapplicable to facts of the case
D.