Which of the following statements about lac-operon is correct?

Which of the following enzymes synthesizes precursor mRNA?

In the lac operon, the $\boldsymbol{z}$ gene codes for

Which of the following statements are correct with reference to a transcription unit?

A. A transcription unit in DNA is defined primarily by three regions : promoter, structural gene and terminator.

B. The promoter is said to be located towards the 5'-end of the structural gene.

C. The promoter is a DNA sequence that provides binding site for RNA polymerase.

D. The promoter defines the template and coding strands.

E. The terminator is located towards the $3^{\prime}$-end of the coding strand and it defines the end of the process of transcription.

Choose the correct answer from the options given below: