How Does the Binding of The $\lambda$ Phage CI Repressor to O_R1 and O_R2 Block Transcription from to O_R1

How does the binding of the $\lambda$ phage cI repressor to O_R1 and O_R2 block transcription from P_R?

A) It prevents the RNA polymerase from transcribing down the gene.
B) It blocks binding of the RNA polymerase to the -10 and -35 sites on the promoter.
C) It terminates transcription at an earlier terminator.
D) It leads to the degradation of the RNA produced from P_R.
E) It activates a promoter that produces an antisense transcript.