Meso "2,3" -dibromo butane is treated with "KI" in acetone. The product formed is
Cis but-2-ene
Trans but-2-ene
But-1-ene
Both (A) and (b)

Meso 2,3 -dibromo butane is treated with KI in acetone. The product formed is (A) Cis but-2-ene (B)Trans but-2-ene (C) But-1-ene . (D) Both (A) and (B).

The product of the reaction But-2-ene+ NBr to ?

When cis-but-2-ene is treated with Br_(2) in "CCl"_(4) medium the product formed will be