What is a step of rho dependent termination?
a. the rho protein acts as an RNA-DNA helicase
b. RNA polymerase stalls at a hairpin loops while it is transcribing a U-rich sequence
c. RNA polymerase stalls at a hairpin loops while it is transcribing a C-rich sequence
d. RNA polymerase stalls at a hairpin loops while it is transcribing an A-rich sequence
e. the rho protein causes RNA polymerase to fall off the DNA