Which of the following reactions will yield 2, 2- Di-bromopropane 

Reaction of propyne by HBr is an addition reaction that follows Markovnikov's rule where Br attached to the carbon atom that has fewer number of hydrogen atoms. Reaction of alkyne with HBr takes place in two steps.

$\begin{array}{ccc}{\mathrm{CH}}_3-\mathrm{C}\equiv \mathrm{CH}+\mathrm{HBr}& \to & {\mathrm{CH}}_3-\mathrm{C}\left(\mathrm{Br}\right)={\mathrm{CH}}_2\\ {\mathrm{CH}}_3-\mathrm{C}\left(\mathrm{Br}\right)={\mathrm{CH}}_2+\mathrm{HBr}& \to & \underset{2,2-\mathrm{Di}-\mathrm{bromopropane}}{{\mathrm{CH}}_3-\mathrm{C}{\left(\mathrm{Br}\right)}_2-{\mathrm{CH}}_3}\end{array}$