Compare all the organisms. What trend do you
see?
The proportions of DNA bases vary greatly
among organisms.
The proportions of DNA bases are similar in
closely related organisms, but different in
organisms that are not closely related.
The proportions of DNA bases are similar
among all organisms.

The genetic variation between humans and orangutans is the greatest is the right option.

Explanation:

A phylogenetic tree is illustration which shows evolutionary relationship between different species. This concept is based on Darwin's descent with modification.

Human and orangutan are 97% similar in their DNA sequences.

The difference in DNA bases shows large genetic variations in both the species.

The species are organized on the basis of traits that are changed over time as compared to their ancestors as they evolve.

Less related species will have more differences in their DNA sequence.

The phylogenetic tree formed indicates that orangutan and human are less related to each other than other species.