What happens when bromine reacts with $CH_3 - C = CH$? How would you justify this reaction ?

Question

$\begin{array}{1 1}\text{(a) 1,1,2 - tri bromo propane is formed}\\\text{(b) 1,1,2,2 - tetra bromo propane is formed}\\\text{(c)1,1 - Di bromo propane is formed}\\\text{(d) Bromo propane is formed}\end{array}$