Which statement below best explains what is meant by the statement, An organocuprate reaction with a ...

Which statement below best explains what is meant by the statement, An organocuprate reaction with a vinyl halide is stereospecific?
 
  A. The reaction of a specific stereoisomer with the R2CuLi reagent will yield that particular stereoisomer as the product.
 
  B. The reaction of a vinyl halide with the R2CuLi reagent will only yield the cis product.
 
  C. The reaction of a vinyl halide with the R2CuLi reagent will only yield the trans product.
  D. The reaction of a vinyl halide with the R2CuLi reagent will only yield one enantiomer producteither R or S configuration.