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 organization or association", specifically "business, trade, professional, or union (BTPU)". Your task is to determine what subcategory of private association best describes this litigant.

Opinion:
Harold E. FERGER, William J. Norton, Patrick F. Norton, and Columbus P. Brittain v. LOCAL 483 OF the INTERNATIONAL ASSOCIATION OF BRIDGE, STRUCTURAL AND ORNAMENTAL IRON WORKERS, AFL-CIO, Appellant.
No. 14996.
United States Court of Appeals Third Circuit.
Argued Feb. 11, 1965.
Decided Feb. 25, 1965.
Thomas L. Parsonnet, Newark, N. J. (Parsonnet & Parsonnet, Newark, N. J., on the brief), for appellant.
D. F. Moore Craig, Newark, N. J. (Bracken & Walsh, Newark, N. J., John J. Bracken, Newark, N. J., on the brief), for appellees.
Before KALODNER, STALEY and FREEDMAN, Circuit Judges.
PER CURIAM.
On review of the record we find no error. The Judgment of the District Court will be affirmed for the reasons so well stated by Judge Meaney in his opinion of May 7, 1964, 238 F.Supp. 1016.

Question: This question concerns the first listed appellant. The nature of this litigant falls into the category "private organization or association", specifically "business, trade, professional, or union (BTPU)". What subcategory of private association best describes this litigant?

Choices:
Business or trade association
utilities co-ops
Professional association - other than law or medicine
Legal professional association
Medical professional association
AFL-CIO union (private)
Other private union
Private Union - unable to determine whether in AFL-CIO
Public employee union- in AFL-CIO (include groups called professional organizations if their role includes bargaining over wages and work conditions)
Public Employee Union - not in AFL-CIO
Public Employee Union - unable to determine if in AFL-CIO
Union pension fund; other union funds (e.g., vacation funds)
Other
Unclear

Answer: 5