The correct answer is option 3, which is Cretaceous. The geological time scale is divided into eras, and the Cretaceous era is the most recent era in the Mesozoic era. The Permian era is older than the Triassic, Cretaceous, and Jurassic eras, so options 1 and 4 are incorrect. The Triassic era is older than the Cretaceous era, so option 2 is also incorrect. The Cretaceous era lasted approximately from 145 to 66 million years ago and is known for the dominance of dinosaurs, as well as significant geological and biological changes, including the emergence of flowering plants. It ended with a mass extinction event that led to the extinction of dinosaurs and allowed mammals to diversify and evolve.