2. In Sanger DNA sequencing, what is the key feature of the dideoxynucleotide (ddNTP)? (A) It only pairs with guanine bases. (B) It contains a sulfur group on the 3' carbon. (C) It lacks both the 2' and 3' hydroxyl group, causing chain termination. (D) It forms extra hydrogen bonds with the template strand. (E) It cuts DNA strands at specific palindromic sequences.