The correct answer is the Federal Court of Appeal.
Decisions of the U.S. Tax Court may be appealed to the Federal Court of Appeal.
The tax court hears the disputes of federal income tax. If there is any nonconformity, a citizen can appeal to the Federal Court of Appeal. The judge can take any time to decide on a case. The Tax court can issue different opinions such as a Bench Opinion, a Summary Opinion, and a Memorandum Opinion. The Summary and Memorandum opinions can be viewed on the website of the Tax Court.