The answer explanation for this question seems to coincide with answer D, however, the given answer is C. Did anyone else find this? Or have I misinterpreted the answer.

Thanks,
Natasha

Agreed with RobertsA. The key to the question is in the passage. Both the RNA polymerases in the passage refer to DNA templates, not RNA templates, which would exclude option D. The passage states magnesium is necessary. And of course to make RNA, you need nucleotides.