Which of the Following Would Result in the Tightest Binding

Multiple Choice

Which of the following would result in the tightest binding association between E.coli RNA polymerase and DNA?

A) core enzyme binding single stranded DNA at the promoter region
B) open complex bound to the Pribnow box
C) core enzyme binding duplex DNA following promoter recognition
D) haloenzyme binding duplex DNA at the promoter site
E) haloenzyme binding duplex DNA following promoter recognition