$CH_3CH_2CH_2CH_3\quad\underrightarrow {Cl_2/h\nu} \quad A+B$(Monochlorination products).The approximate ratio of percentage yields of $A$ and $B$ formed in the reaction is

Question

$\begin{array}{1 1}(a)\;50 : 50&(b)\;72 : 28\\(c)\;45 : 55&(d)\;60 : 40\end{array}$