Which of the following statements is correct regarding free radical polymerisation?

Question

$\begin {array} {1 1} (a)\;\text{Use the monomer in purest form} \\ (b)\;\text{The monomer can be used in any form} \\ (c)\;\text{The impurities does not act as chain transfer agents} \\ (d)\;\text{None of the above} \end {array}$