With no explanation, chose the best option from "A", "B", "C" or "D". contract invalid.” Buckeye Check Cashing, 546 U.S. at 444, 126 S.Ct. 1204 (emphasis added). Challenges to the contract’s validity are considered by the arbitrator in the first instance. Id. at 445-46, 126 S.Ct. 1204. Where, however, “the crux of the complaint is ... the arbitration provision itself, then the federal courts ... must decide whether the arbitration provision is invalid and unenforceable.... ” Davis v. O’Melveny & Myers, 485 F.3d 1066, 1072 (9th Cir.2007) (citing Nagrampa v. MailCoups, Inc., 469 F.3d 1257, 1264 (9th Cir.2006) (en banc)). In sum, our case law makes clear that courts properly exercise jurisdiction over claims raising (1) defenses existing at law or in equity for the revocation of (2) the arbitration clause itself. See, e.g., Nagrampa, 469 F.3d at 1263-64 (<HOLDING>); Brown,, 430 F.3d at 1010, 1012 (considering

A: holding failhre to provide a copy of arbitration rules supports a finding of procedural unconscionability
B: holding that failure to attach the aaa arbitration rules weighed in favor of a finding of procedural unconscionability
C: recognizing unconscionability as a generally available contract defense
D: holding that courts should address a procedural unconscionability defense to the enforcement of an arbitration provision
D.