In lac operon, the genes a,i,y and z code respectively for :
A. repressor protein, permease, `beta`-galactosidase, transacetylase
B. transacetylase, permease, `beta`-galactosidase, repressor protein
C. permease, transacetylase, repressor protein, `beta`-galactosidase
D. tranacetylase, repressor protein, permease, `beta`-galactosidase
