Why Did Li and Other University of Chicago Scientists Choose

Why did Li and other University of Chicago scientists choose to conduct DNA sequencing on sections of DNA not encoding proteins?

A) Segments not encoding proteins would show less variability, due to relatively slow and consistent mutation rates.
B) The biotechnology necessary to sequence genes would be technologically much less reliable than for the non-encoding sequences.
C) They would have expected to find only two alleles for each gene, which would have been insufficient for testing the hypothesis.
D) Segments not encoding proteins would show more variability, due to adaptations associated with different habitats.
E) Segments not encoding proteins are common to many more species, so a type of experimental control was established.