With no explanation, chose the best option from "A", "B", "C" or "D". governed by the procedural framework established in McDonnell Douglas v. Green, 411 U.S. 792, 93 S.Ct. 1817, 36 L.Ed.2d 668 (1973). Plaintiff first must establish a prima facie case of retaliation. If plaintiff succeeds, defendants may rebut plaintiffs prima facie case by disputing the facts or by offering a “legitimate, nondiscriminatory reason” for their actions. Id. at 802, 93 S.Ct. 1817. If defendants set forth a successful rebuttal, plaintiff must prove that the reason defendants offered for their actions was merely pretextual. Id. at 804, 93 S.Ct. 1817. This burden shifting framework, initially established to cover private discrimination claims under Title VII, also applies to federal employees claiming retaliation. See, e.g., Mitchell v. Baldrige, 759 F.2d 80, 86 (D.C.Cir.1985) (<HOLDING>). To prove a prima facie case of retaliation,

A: holding that even if employee established prima facie case of retaliation he produced no evidence challenging employers reason for firing him
B: holding that federal government employee successfully established prima facie case of retaliation under mcdonnell douglas but failed to prove employers proffered reason was pretextual
C: recognizing that whether the employee uses the mcdonnell douglas framework or other evidence to create a prima facie case when the employer offers a legitimate nondiseriminatory reason for its adverse action the question is whether a rational trier of fact could conclude that the employers action was taken for impermissibly discriminatory reasons
D: holding that a plaintiff who could not demonstrate every element of the mcdonnell douglas test could nonetheless demonstrate a prima facie case
B.