With no explanation, chose the best option from "A", "B", "C" or "D". an understandable mistake has been made.” Fed. R. Civ. P. 17, Advisory Committee’s Notes to the 1966 Amendments (emphasis added). Accordingly, most courts have applied this part of Rule 17(a) only when the plaintiff brought the action in his or her own name because determination of the real party in interest was difficult or when an understandable mistake was made. See, e.g., Crowder v. Gordons Transps., Inc., 387 F.2d 413 (8th Cir. 1967) (plaintiffs mistake was “understandable and excusable” where case involved a conflicts-of-law question with respect to whether Arkansas or Missouri law applied, and each state’s wrongful-death statute designated a different person as the real party in interest). See also Advanced Magnetics, Inc. v. Bayfront Partners, Inc., 106 F.3d 11 (2d Cir. 1997) (<HOLDING>). This court has recognized the “understandable

A: holding that the district court erred in failing to properly charge the jury on defendants affirmative defenses
B: holding that district court erred in failing to consider evidence of secondary considerations
C: holding district court erred in failing to permit substitution of plaintiffs to relate back under rule 15c and 17a where advanced magnetics was mistaken about the legal effect of a shareholder assignment
D: holding that where the plaintiffcorporation lacked standing to pursue its shareholders claims the district court erred in refusing to allow substitution of shareholders as plaintiffs under rule 17a3
C.