With no explanation, chose the best option from "A", "B", "C" or "D". has sixty days after the judgment to file a notice of appeal. Fed. R.App. P. 4(a)(1)(B). Although the parties no longer contest the timeliness of this appeal, the timely filing of an appeal is “mandatory and jurisdictional.” Acevedo-Villalobos v. Hernandez, 22 F.3d 384, 387 (1st Cir.1994) (internal quotation marks omitted). Therefore, unless the sixty-day rule applies, we must dismiss for lack of jurisdiction. See id. (noting that court “lack[s] jurisdiction over late appeals”). The United States, its officer, or agency is a “party” to a case not only where it is a named party to the appeal, see In re Lloyd, Carr, & Co., 617 F.2d 882, 884 n. 1 (1st Cir.1980), but also where it has actively participated in the proceedings, see id.; cf. In re Serrato, 117 F.3d 427, 429 (9th Cir.1997) (<HOLDING>). This appeal encompasses challenges to two

A: holding that defendant did not waive special appearance
B: holding that us trustee did not become party merely by his involuntary appearance to quash a summons
C: holding that defendant did not waive his special appearance by filing a motion for new trial subject to the special appearance
D: holding that party waived special appearance
B.