Read the following excerpt from a US court opinion:
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arid mandatory right originating outside of the CBA. see e.g., Rabe v. United Air Lines, Inc., 636 F.3d 866, 873 (7th Cir.2011) (“A state law claim is preempted only when it asserts rights or obligations arising under a collective bargaining agreement or when its resolution is substantially dependent on the terms of the collective bargaining agreement.”); Detabali v. St. Luke’s Hospital, 482 F.3d 1199, 1203 (9th Cir.2007) (“[T]he need to interpret the [collective bargaining agreement] must inhere in the nature of the plaintiffs claim.. If the claim is plainly based on state law, § 301 preemption is not mandated simply because the defendant refers to the [collective bargaining agreement] in mounting a defense.”); Harper v. AutoAlliance Int’l, Inc., 392 F.3d 195, 209 (6th Cir.2004) ; Trevino v. Ramos, et al., 197 F.3d 777, 781
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What is the most suitable continuation to the opinion? Your options are:
A. holding that plaintiffs state law claim against a nonsignatory to the cba was preempted by  301
B. holding that an employees retaliation claim was not preempted by section 301 because he was exercising his rights under the states antidiscrimination laws and the terms of the cba were at most relevant background for the employees termination
C. holding that a company exercising substantial control of the terms and conditions of the work of the employees is an employer under the flsa
D. holding that plaintiffs negligence claim was preempted by section 301 because employers duty to provide a safe workplace was expressly created by the cba
E. holding that both plaintiffs discrimination and retaliation claims were beyond the preemptive scope of section 301 because they involved purely factual questions and asserted rights independent of the cba
Reply with [A, B, C, D, E] only.