Which statement about sanger sequencing is false?

(a) because a dideoxynucleotide lacks the 3'-hydroxyl group, the next nucleotide cannot be added, and therefore dna synthesis is blocked at the point of addition.
(b) four different arrays of labeled dna chains increasing in length by one base are produced.
(c) if the tag is a fluorescent dye and a different fluorescent color emitter is used for each of the four ddntp reactions, then the four reactions can take place in the same test tube and the four sets of nested dna chains can undergo electrophoresis together.
(d) to read the dna sequence of the synthesized strand in the 5'-to-3' direction, the gel is read from top to bottom.