Which of the following best describes the ability of an enhancer to mediate transcription from very distant sites?
a. Looping of the DNA can occur, allowing the transcription factor to get into the proximity of the RNA polymerase.
b. When needed, enhancers are spliced into a region of closer proximity to the promoter.
c. They are recognized by RNA polymerase, which bind and then slide down the promoter toward the gene.
d. All of the other choices