19. For cloning of genomic DNA sequences, yeast artificial chromosome (YAC) and bacterial artificial chromosome (BAC) are two popular cloning vector systems. Which of the following is NOT correct? (A) A BAC would be circular and a YAC would be linear. (B) A YAC would have telomeres and a BAC would not. (C) A YAC would have a centromere and a BAC would not. (D) A YAC would be bound to histones in the cell and a BAC would not. (E) A BAC would contain a much larger DNA insert than a YAC.