A Synthetic Strategy for Converting Trans-2-Butene into Pure Cis-2-Butene Would

A synthetic strategy for converting trans-2-butene into pure cis-2-butene would consist of which of the following?

A) Reaction with H₂,Ni₂B (P-2)
B) Reaction with i) Br₂,CCl₄; ii) 2 NaNH₂,NH₃(l) ; iii) Na,NH₃ (l)
C) Reaction with H₃O⁺,heat
D) Reaction with i) Br₂,CCl₄; ii) 2 NaNH₂,NH₃(l) ; iii) H₂,Ni₂B (P-2)
E) None of these will successfully effect the desired transformation.