What is the legal test required by Rule 901 to authenticate an item of evidence?

Rule 901 does not definitively establish the nature or quantum of proof that is required preliminarily to authenticate an item of evidence. Id. at 499. The type and quantum of evidence required is related to the purpose for which the evidence is offered, id. at 488, and depends upon a context-specific determination whether the proof advanced is sufficient to support a finding that the item in question is what its proponent claims it to be. We have said that [t]he bar for authentication of evidence is not particularly high. United States v. Gagliardi, 506 F.3d 140, 151(2d Cir.2007). But even though [t]he proponent need not rule out all possibilities inconsistent with authenticity, or ... prove beyond any doubt that the evidence is what it purports to be, id. (internal quotation marks omitted), there must nonetheless be at least sufficient proof ... so that a reasonable juror could find in favor of authenticity or identification, Pluta, 176 F.3d at 49 (internal quotation marks omitted).