With no explanation, chose the best option from "A", "B", "C" or "D". that the “explanation is ‘unworthy of credence’ or by offering other forms of circumstantial evidence sufficiently probative of [retaliation].” Mereish v. Walker, 359 F.3d 330, 336 (4th Cir.2004) (quoting Tex. Dep’t of Cmty. Affairs v. Burdine, 450 U.S. 248, 256, 101 S.Ct. 1089, 67 L.Ed.2d 207 (1981)). To prove a prima facie case of retaliation, Plaintiff must show that (1) she engaged in a legally-protected activity; (2) an adverse employment action was taken against her; and (3) there was a casual connection between the first two elements. Dowe, 145 F.3d at 656; Spriggs, 242 F.3d at 190. Plaintiff has established the first two of these elements. She suffered an adverse employment action when she was terminated. Laughlin v. Metro. Wash. Airports Auth., 149 F.3d 253, 258 (4th Cir.1998) (<HOLDING>). Moreover, Plaintiff filed a formal complaint

A: holding that suspension with pay was not adverse employment action
B: holding that termination is an adverse employment action
C: holding that reduction in workload is an adverse employment action
D: holding a mere warning that termination is possible does not per se constitute adverse employment action
B.