48. Transcription of the lactose operon in E. coli is stimulated by: (A) a mutation in the repressor gene that strengthens the affinity of the repressor for the operator. (B) a mutation in the repressor gene that weakens the affinity of the repressor for the operator. (C) a mutation in the repressor gene that weakens the affinity of the repressor for the inducer. (D) binding of the repressor to the operator. (E) the presence of glucose in the growth medium.