With no explanation, chose the best option from "A", "B", "C" or "D". on past practice, and that therefore, the Company was entitled to deny the Union the information. The Company’s argument relies on TCI of New York, Inc., 301 N.L.R.B. No. 122, 136 L.R.R.M. (BNA) 1277 (1991), wherein the Board construed a zipper clause stating: “This agreement ... supersedes all prior agreements, understandings and past practices, oral or written, expressed or implied.” The Board found this language to be a waiver by the Union of past practices. Relying on that zipper clause, the Board allowed the employer unilaterally to eliminate a ten-year past practice of paying year-end bonuses to bargaining unit employees without further bargaining. See also Columbus & Southern Ohio Electric Co., 20 N.L.R.B. 686, aff'd sub. nom. IBEW Local 1466 v. NLRB, 795 F.2d 150 (D.C.Cir.1986) (<HOLDING>). The Company emphasizes the similarity of the

A: holding that historical practice is important when courts interpret the constitution even when the nature or longevity of that practice is subject to dispute and even when that practice began after the founding era
B: holding that a zipper clause similar in language to tci and to the zipper clause in the present ease was a waiver of past practice allowing the employer to unilaterally discontinue a fortyyear past practice of christmas bonuses
C: holding out admission to practice law when not admitted to practice
D: holding that the term manufacture applied not only to things made but to the practice of making to principles carried into practice in a new manner to new results of principles carried into practice
B.