Answer:
Enzymes refer to a substance that gets generated within a living species and performs a particular kind of a biochemical reaction by working as a catalyst. The concentration of the enzyme present within the cells can get modified by regulating the rate of the production of enzymes and also the rate of its degradation.
Thus, regulating the steps of translation, transcription, and degradation of the enzyme would be the ideal choices as all these will determine the concentration of the enzyme present within the cells. Hence, the correct options are A, B, and C. The option D is not correct as the allosteric regulator only helps in changing the activity of an enzyme.