What follows is an opinion from a United States Court of Appeals.
Intervenors who participated as parties at the courts of appeals should be counted as either appellants or respondents when it can be determined whose position they supported. For example, if there were two plaintiffs who lost in district court, appealed, and were joined by four intervenors who also asked the court of appeals to reverse the district court, the number of appellants should be coded as six.
When coding the detailed nature of participants, use your personal knowledge about the participants, if you are completely confident of the accuracy of your knowledge, even if the specific information is not in the opinion. For example, if "IBM" is listed as the appellant it could be classified as "clearly national or international in scope" even if the opinion did not indicate the scope of the business. 

Your task concerns the first listed appellant. The nature of this litigant falls into the category "private business (including criminal enterprises)", specifically "transportation". Your task is to determine what subcategory of business best describes this litigant.

Opinion:
AMERICAN PRESIDENT LINES, Ltd., Appellant, v. FEDERAL MARITIME BOARD et al., Appellees.
No. 12914.
United States Court of Appeals District of Columbia Circuit.
Argued March 20, 1956.
Decided May 3, 1956.
Mr. Warner W. Gardner, Washington, D. C., with whom Mr. Alfred L. Scanlan, Washington, D. C., was on the brief, for appellant.
Mr. Edward H. Hickey, Atty., Dept, of Justice, with whom Messrs. Leo A. Rover, U. S. Atty., at the time the record was filed, Edward D. Ransom, Gen. Counsel, Federal Maritime Board, and Paul A. Sweeney, Atty., Dept, of Justice, were on the brief, for appellees.
Before WILBUR K. MILLER, BAZELON and BASTIAN, Circuit Judges.
PER CURIAM.
Plaintiff (appellant), American President Lines, Ltd., a subsidized shipping operator, filed this action for a declaratory judgment against the defendants (appellees), the Federal Maritime Board and its individual members. The complaint sought a judgment that the term “capital necessarily employed in the business,” contained in General Order 31 issued under § 607(d) of the Merchant Marine Act of 1936, as amended, must be used by appellees rather than the definition of that term contained in General Order 71, as amended, in computing the net amount of the subsidy inuring to appellant under its operating-differential subsidy contract with the United States for the period January 1, 1947 to September 30, 1948.
The District Court dismissed for lack of jurisdiction upon the ground, among others, that Congress had given appellant “a clear remedy” in the Court of Claims which “unquestionably has the right to consider and determine the validity of the action of the Board, * * * Since we agree, it is unnecessary for us to consider the other grounds relied upon by the District Court.
Affirmed.
. D.C.1955, 133 F.Supp. 100, 103.
. Appellant contends that its Court of Claims remedy is inadequate because that court cannot relieve it of the obligation to maintain an unnecessarily high special reserve fund under § 607(c) of the Act, 46 U.S.C.A. § 1177(c). Diminution of the fund is required by the statute to have the approval of the Board. In the face of a judgment by the Court of Claims determining that the definition in General Order 71 is invalid, the Board would be arbitrary in the extreme to withhold approval of a withdrawal from the fund solely on the basis of the definition. Wo agree with Judge Morris that, if tbe Court of Claims should uphold appellant’s view of the definition, appellant “would receive the complete relief it seeks, even as to those funds which it is required to deposit in the special reserve fund.” Id. at page 103.

Question: This question concerns the first listed appellant. The nature of this litigant falls into the category "private business (including criminal enterprises)", specifically "transportation". What subcategory of business best describes this litigant?

Choices:
railroad
boat, shipping
shipping freight, UPS, flying tigers
airline
truck, armored cars
other
unclear

Answer: 1