All of the following help the cell regulate gene expression during Step 2 of protein formation EXCEPT
A. general factors that are required for the RNA polymerase to bind to the promoter
B. repressors binding to the operator preventing the RNA polymerase from progressing
C. specialty factors binding to the RNA polymerase, altering its specificity
D. tRNA that binds to the RNA polymerase in the presence of complementary mRNA