____ 4.By mistake, DNA fragments were loaded onto a gel using a buffer with a pH so low that all the phosphate groups of the DNA nucleotides were protonated (i.e., had H+ ions added to them.) Subsequent electrophoresis failed to separate the fragments. This was because [I OBJ:6.1]

Question

a. the voltage difference across the gel was inadequate
b. the double-stranded fragments became single-stranded and all migrated very swiftly to the positive pole
c. the fragments joined together into one huge molecule
d. the fragments had very little charge, and thus were not attracted to the positive pole
e. "the fragments became circular"