What follows is an opinion from the Supreme Court of the United States. Your task is to determine the bases on which the Supreme Court rested its decision with regard to the legal provision that the Court considered in the case. Consider "judicial review (national level)" if the majority determined the constitutionality of some action taken by some unit or official of the federal government, including an interstate compact. Consider "judicial review (state level)" if the majority determined the constitutionality of some action taken by some unit or official of a state or local government. Consider "statutory construction" for cases where the majority interpret a federal statute, treaty, or court rule; if the Court interprets a federal statute governing the powers or jurisdiction of a federal court; if the Court construes a state law as incompatible with a federal law; or if an administrative official interprets a federal statute. Do not consider "statutory construction" where an administrative agency or official acts "pursuant to" a statute, unless the Court interprets the statute to determine if administrative action is proper. Consider "interpretation of administrative regulation or rule, or executive order" if the majority treats federal administrative action in arriving at its decision.Consider "diversity jurisdiction" if the majority said in approximately so many words that under its diversity jurisdiction it is interpreting state law. Consider "federal common law" if the majority indicate that it used a judge-made "doctrine" or "rule; if the Court without more merely specifies the disposition the Court has made of the case and cites one or more of its own previously decided cases unless the citation is qualified by the word "see."; if the case concerns admiralty or maritime law, or some other aspect of the law of nations other than a treaty; if the case concerns the retroactive application of a constitutional provision or a previous decision of the Court; if the case concerns an exclusionary rule, the harmless error rule (though not the statute), the abstention doctrine, comity, res judicata, or collateral estoppel; or if the case concerns a "rule" or "doctrine" that is not specified as related to or connected with a constitutional or statutory provision. Consider "Supreme Court supervision of lower federal or state courts or original jurisdiction" otherwise (i.e., the residual code); for issues pertaining to non-statutorily based Judicial Power topics; for cases arising under the Court's original jurisdiction; in cases in which the Court denied or dismissed the petition for review or where the decision of a lower court is affirmed by a tie vote; or in workers' compensation litigation involving statutory interpretation and, in addition, a discussion of jury determination and/or the sufficiency of the evidence.

UNITED STATES POSTAL SERVICE v. NATIONAL ASSOCIATION OF LETTER CARRIERS, AFL-CIO
No. 87-59.
Argued April 20, 1988
Decided April 27, 1988
Glen D. Nager argued the cause for petitioner. With him on the briefs were Solicitor General Fried, Assistant Attorney General Willard, Deputy Solicitor General Wallace, William Kanter, and Marc Richman.
Keith E. Secular argued the cause and filed a brief for respondent.
Briefs of amici curiae urging affirmance were filed for the American Federation of Labor and Congress of Industrial Organizations by David M. Silberman and Laurence Gold; and for the National Council on Compulsive Gambling, Inc., by Albert B. Lewis.
Per Curiam.
The writ of certiorari is dismissed as improvidently granted.

Question: What is the basis of the Supreme Court's decision?
A. judicial review (national level)
B. judicial review (state level)
C. Supreme Court supervision of lower federal or state courts or original jurisdiction
D. statutory construction
E. interpretation of administrative regulation or rule, or executive order
F. diversity jurisdiction
G. federal common law
Answer: