Match List-I (RNA polymerase parts) with List-II (Functions) and select the correct answer:

List-I	List-II
a. Sigma factor	1. Ineffective in transcribing RNA, because it transcribes both strands
b. The core enzyme	2. Transcribes only one strand of the DNA template
c. The holozyme	3. Interacts with the core enzyme to form the complete enzyme
d. The β-subunit	4. Required for the interaction with the sigma factor