26.The repair of a double-strand break can be accomplished by__________，which requires the Ku70/80 protein to___________. (A) nonhomologous end joining; catalyze blunt end ligation (B) nonhomologous end joining: bind to both ends of the break (C) homologous recombination; catalyze blunt end ligation (D) homologous recombination; bind to both ends of the break (E) none of the above