In the Past, Species of Sponges, Cnidarians, and Ctenophores Were

In the past, species of sponges, cnidarians, and ctenophores were referred to as "lower" or "primitive" animals because of their relatively simple body plans and lack of any sophisticated organ differentiation. Which of the following suggest that the terms "lower" or "primitive" are NOT useful as descriptors for these organisms?

A) Many members of these groups are active predators and feed on other organisms.
B) These groups have been around for millions of years, therefore their evolutionary path has been successful in spite of limited complexity.
C) These groups are not primary producers, therefore should not be classified as "lower" because they occur higher on the trophic pyramid.
D) These groups harbor a lot of genetic variation, "lower" groups would have less evolved genomes.