The correct option is D Dinosaurs
The Mesozoic era is the age of the dinosaurs and lasted almost 180 million years from approximately 250 to 65 million years ago. This era includes 3 well known periods, called the Triassic, Jurassic, and Cretaceous periods. A mass-extinction marked the beginning and end of the Mesozoic era. The event that caused the transition from the Paleozoic era to the Mesozoic era was the greatest extinction this earth has seen. This extinction wiped out about 95% of all marine life and 70% of land-life. This allowed the dinosaurs to step in and settle into their role as the lords of the earth. The era ended with "The Great Extinction", which marked the end of the dinosaurs as the Cenozoic era began. So, mesozoic era is associated with the mass extinction of dinosaurs. Thus, option D is correct.
There were no flowering plants or dodo or trilobites in mesozoic era. Thus, other options are wrong.