To Better Understand the Genetic Basis of Human Diseases, Would

To better understand the genetic basis of human diseases, would it be better to sequence 1000 human genomes or 1000 genomes of closely related species? ​

A) 1000 genomes of closely related species, because animals exhibit disease symptoms more clearly than humans do
B) 1000 genomes of closely related species, because it is easier to sequence animal genomes than human genomes ​
C) 1000 human genomes, because this would give a better indication of the evolutionary history of disease-causing genes ​
D) 1000 human genomes, because this would give a better indication of the link between specific human genes and genetic disorders ​
E) neither would be beneficial because human disease is almost entirely caused by environmental factors ​