The correct answer is: "the US Congress"
The US Tax Court is a federal trial court that was founded by the US Congress, complying with article I of the US Constitution (section 8) that entitles the Congress to establish courts with an inferior jurisdiction than that of the US Supreme Court.
The Tax Court is in charge of disputes related to the federal income tax. Tax matters can be litigated in different settings but this court is the only manner through which taxpayers can do so without having first paid the abovementioned disputed tax in full.
