So, the mural only has some species- but we don't know which one, living in harmony. We don't know whether it's humans and we have no reason to think that it might be humans.
So it can't be A) or D) - those are connected with human activities.
it's informative to the public about this species so the correct answer is
B. 'Educating the public about the natural environment'
To contrast current artists in the Italian Renaissance, which has art commonly known for beauty and symmetry.