Now, this one is truly hard. So I suggest you reread each's article or browse each's gallery first before voting.
Simone Holtznagel is an Australian fashion model and reality star. She gained prominence after appearing on the famous show Australia’s Next Top Model. Her popularity continued to soar as she went on to work with world-renowned brands such as ‘Guess’ and ‘Playboy’. Read more about her in this Simone Holtznagel article.
Crystal Renn is an American fashion model and author. She is also an actress and writer, known for The Puppet Man in 2016 and Now Wakes the Sea in 2017. Crystal also appeared in the 2012 Sports Illustrated Swimsuit Issue. Learn more about her in this Crystal Renn article.