To synthesize insulin on a large scale basis, the most suitable staing material obtained fro the beta cells of the pancreas is:

D i.e. mRNA of insulin Insulin is synthesized on a large scale basis from complementary DNA's (cDNA), using recombinant technology. But cDNA is not the staing material. cDNA are derived from mRNAQ.Thus mRNA is staing material for insulin synthesis on a large scale basis.Construction of cDNA from mRNA