Which of the following epochs marks the major radiation of modern birds?

Step-by-step solution

The question asks for the epoch that marks the major radiation of modern birds. The extinction of non-avian dinosaurs at the end of the Cretaceous period (Mesozoic era) left many ecological niches vacant. In the subsequent Cenozoic era, modern birds (Neornithes) underwent a rapid and massive evolutionary radiation to fill these niches. The Palaeocene epoch (the first epoch of the Cenozoic era) is widely recognized in evolutionary biology and paleontology as the time when the major adaptive radiation of modern birds