This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
To initiate transcription RNA polymerase does not require which one of the following: 
Select and explain. 
A. Template (ds DNA), B. Activated precursors (ATP, GTP, UTP, CTP), C. Divalent metal ions (Mn2+, Mg2+), D. Primer
D: Primer
Answer: D: Primer 
Explanation: DNA polymerase can only elongate existing polynucleotide chains, and thus requires a primer. RNA polymerase can initiate RNA synthesis de novo and hence does not require a primer. Ref: Molecular Biology of the Gene Watson, 2004, Page 376 ; Lippincott's Illustrated Q & A Review of Biochemistry by Michael A. Lieberman, Rick Ricer, 2009, Page 294