Why Are Dideoxynucleotides Added to the Reaction in the Sanger

Why are dideoxynucleotides added to the reaction in the Sanger sequencing methodology?

A) They label the DNA strands
B) They cause termination of the replicating strand
C) They allow longer processivity of the DNA polymerase
D) They cement the newly synthesized strand to the template strand
E) There is a lower chance of mutation during the sequencing reaction