$\begin{array}{1 1}(a)\;\text{It involves free radical addition}\\(b)\; \text{The presence of carbon tetrachloride in styrene polymerisation results in lowering of average molecular mass of the polymer}\\(c)\;\text{The presence of benzoquinone increases the polymerisation process}\\(d)\;\text{The presence of }CCl_4\text{ acts as inhibition}\end{array}$
